How to find valence electrons

How to find valence electrons

The number of valence electrons for molecules can be calculated by adding the valence electrons of all the atoms that form that respective molecule.

Here are some examples

#CO_2# : Each carbon dioxide molecule is formed from 1 C atom and 2 O atoms. We know that C has 4 valence electrons and that O has 6 valence electrons, which means that the number of valence electrons for 1 #CO_2# molecule will be

#1 * 4 + 2 * 6 = 16e^-#

#H_2O# : Again, each water molecule is formed from 1 O atom and 2 H atoms. Since the number of valence electrons for O and H are 6 and 1, respectively, one molecule of water will have

#2 * 1 + 1 * 6 = 8# valence electroncs.

#H_2SO_4# : One molecule of sulfuric acid has 2 H atoms, 1 S atom, and 4 O atoms, each contributing 1, 6, and 6 valence electrons. So the number of valence electrons for 1 molecule of sulfuric acid is

#2 * 1 + 1 * 6 + 4 * 6 = 32e^-# .

Here’s a video showing more examples:

  • December 5, 2021
  • Posted by Gabi

Core Concepts

In this tutorial, we learn about valence electrons, what they are, and why they are significant. We will also learn how to tell how many valence electrons an element has.

Topics Covered in Other Articles

What are valence electrons? Why are they significant?

Valence electrons are electrons that located in the outermost electron shell of an atom. These electrons, being the furthest from the nucleus and thus the least tightly held by the atom, are the electrons that participate in bonds and reactions. This also means that the number of valence electrons that an element has determines its reactivity, electronegativity, and the number of bonds it can form.

For example, in the figure below showing a simplified diagram of sodium’s electrons, the valence electron is shown in red. It is located on the outermost shell (in this case, the shell resembles a ring).

The term valence refers to the ability of an element to form bonds with other atoms. An element’s valence was historically determined by how many hydrogen atoms it could bond to (which is determined by how many valence electrons it has available for bonding): for example, carbon can form CH4 so it has a valence of 4, and 4 valence electrons. On the other hand, nitrogen can form NH3 so it has a valence of 3, and 3 valence electrons.

How many valence electrons does an element have?

You can use the periodic table to help you determine how many valence electrons an element (specifically, a neutral atom of the element) has. Look at the group that the element is in, as the group number indicates the number of valence electrons that the element has.

Note, however, that this rule only applies to elements that are not transition metals. Transition metals have more complicated electron configurations. Thus you should take a look at the element’s specific electron shell configuration to figure it out.

This also means that when looking at a group number, exclude the transition metals. They are located in the block in the middle of the periodic table. In this sense, groups 1 and 2 in the diagram below stay the same, but group 13 is our new “group 3”, group 14 is our new “group 4,” and so on.


For example, sodium is in group 1, indicating it has one valence electron. To confirm this, we can check its electron shell configuration: 1s 2 2s 2 2p 6 3s 1 . As we can see, there is one electron in the 3s orbital, which is the outermost one.

Another example is that of chlorine. Chlorine is in group 7, indicating it has seven valence electrons. To confirm this, we can take a look at its electron shell configuration: 1s 2 2s 2 2p 6 3s 2 3p 5 . As we can see, there are seven electrons in the 3s and 3p orbitals combined, which together make up the outermost third orbital.

Lastly, we can take a look at carbon, which is in group 4. From this, we infer it has four valence electrons. To confirm, we check with its electron shell configuration: 1s 2 2s 2 2p 2 . As we can see, there are four electrons in the 2s and 2p orbitals combined, which together make up the outermost second orbital.

A noteworthy case is that of group 8: elements in this group have eight electrons, which makes a full octet. That makes these elements special, known as the noble gases. They have virtually no valence electrons available for bonding or reacting because the full octet of their electron shell is so stable.

A valence electron is an electron that is associated with an atom, and that can participate in the formation of a chemical bond; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair. The presence of valence electrons can determine the element’s chemical properties and whether it may bond with other elements: For a main group element, a valence electron can only be in the outermost electron shell.

An atom with a closed shell of valence electrons (corresponding to an electron configuration \(s^2p^6\)) tends to be chemically inert. An atom with one or two valence electrons more than a closed shell is highly reactive, because the extra valence electrons are easily removed to form a positive ion. An atom with one or two valence electrons fewer than a closed shell is also highly reactive, because of a tendency either to gain the missing valence electrons (thereby forming a negative ion), or to share valence electrons (thereby forming a covalent bond).

Like an electron in an inner shell, a valence electron has the ability to absorb or release energy in the form of a photon. An energy gain can trigger an electron to move (jump) to an outer shell; this is known as atomic excitation. Or the electron can even break free from its associated atom’s valence shell; this is ionization to form a positive ion. When an electron loses energy (thereby causing a photon to be emitted), then it can move to an inner shell which is not fully occupied.

The number of valence electrons

The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized. With the exception of groups 3–12 (the transition metals), the units digit of the group number identifies how many valence electrons are associated with a neutral atom of an element listed under that particular column.

The periodic table of the chemical elements

Periodic table group Valence Electrons
Group 1 (I) (alkali metals) 1
Group 2 (II) (alkaline earth metals) 2
Groups 3-12 (transition metals) 2* (The 4s shell is complete and cannot hold any more electrons)
Group 13 (III) (boron group) 3
Group 14 (IV) (carbon group) 4
Group 15 (V) (pnictogens) 5
Group 16 (VI) (chalcogens) 6
Group 17 (VII) (halogens) 7
Group 18 (VIII or 0) (noble gases) 8**

* The general method for counting valence electrons is generally not useful for transition metals. Instead the modified d electron count method is used. ** Except for helium, which has only two valence electrons.

The Concept of Open Valence ("Valence")

The valence (or valency) of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules. The concept of valence was developed in the last half of the 19th century and was successful in explaining the molecular structure of many organic compounds. The quest for the underlying causes of valence lead to the modern theories of chemical bonding, including Lewis structures (1916), valence bond theory (1927), molecular orbitals (1928), valence shell electron pair repulsion theory (1958) and all the advanced methods of quantum chemistry.

The combining power or affinity of an atom of an element was determined by the number of hydrogen atoms that it combined with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of two; and in hydrogen chloride, chlorine has a valence of 1. Chlorine, as it has a valence of one, can be substituted for hydrogen, so phosphorus has a valence of 5 in phosphorus pentachloride, PCl5. Valence diagrams of a compound represent the connectivity of the elements, lines between two elements, sometimes called bonds, represented a saturated valency for each element. [ 1 ] Examples are:-

Compound H2 CH4 C3H8 C2H2 NH3 NaCN H2S H2SO4 Cl2O7
Diagram How to find valence electrons
Valencies Hydrogen 1 Carbon 4
Hydrogen 1
Carbon 4
Hydrogen 1
Carbon 4
Hydrogen 1
Nitrogen 3
Hydrogen 1
Sodium 1
Carbon 4
Nitrogen 3
Sulfur 2
Hydrogen 1
Sulfur 6
Oxygen 2
Hydrogen 1
Chlorine 7
Oxygen 2

Valence only describes connectivity, it does not describe the geometry of molecular compounds, or what are now known to be ionic compounds or giant covalent structures. The line between atoms does not represent a pair of electrons as it does in Lewis diagrams.

Electrons orbit around the nucleus of an atom at set energy levels known as principal energy levels, or electron shells. Each electron shell is composed of one or more subshells. By definition, valence electrons travel in the subshell farthest away from the nucleus of the atom. Atoms tend to accept or lose electrons if doing so will result in a full outer shell. Accordingly, valence electrons directly influence how elements behave in a chemical reaction.

Finding Valence Electrons for All Elements Except Transition Metals

Locate the desired element on the periodic table. Each square on the periodic table contains the letter symbol for an element printed directly below the atomic number of the element.

For example, locate the element oxygen on the table. Oxygen is represented by the symbol “O” and has an atomic number of 8.

Determine the group number and period number of the element. The vertical columns of the periodic table, counting left to right, 1 through 18, are called groups. In the periodic table, elements with similar chemical properties are in the same group. The horizontal rows of the periodic table, from 1 to 7, are called periods. Periods correspond to the number of electron shells possessed by atoms of the elements in that row.

Oxygen is found in Period 2, Group 16.

Apply the rule of the periodic table to your element. The rule is as follows: If an element is not a transition metal, then valence electrons increase in number as you count groups left to right, along a period. Each new period begins with one valence electron. Exclude groups 3 through 12. These are transitional metals, which have special circumstances.

Following this rule: Elements in group 1 have one valence electron; elements in group 2 have two valence electrons; elements in group 13 have three valence electrons; elements in group 14 have four valence electrons; and so forth up to group 18. elements in group 18 have eight valence electrons, except for helium, which has only two.

Oxygen is located in group 16 on the periodic table, so it has six valence electrons.

Finding Valence Electrons for Transition Metals

How to find valence electrons

Be aware of the unique electron configuration of transition metals.

Valence electrons are generally what is left over after all the inner subshells of an atom have been filled. However, transitional metals may have subshells that are not completely filled. An atom may tend to accept or lose electrons from an incomplete subshell if doing so will result in a full subshell, so subshell electrons may behave like valence electrons. By strict definition, most transitional metals have two valence electrons, but may have a larger range of apparent valence electrons.

Locate the transition metal on the periodic table and make note of the group number. Use iron as an example, a transitional metal with the symbol Fe, atomic number 26 , located at period 4, group 8.

How to find valence electrons

Determine the range of apparent valence consulting the following table:

Group 3: 3 valence electrons Group 4: 2-4 valence electrons Group 5: 2-5 valence electrons Group 6: 2-6 valence electrons Group 7: 2-7 valence electrons Group 8: 2-3 valence electrons Group 9: 2-3 valence electrons Group 10: 2-3 valence electrons Group 11: 1-2 valence electrons Group 12: 2 valence electrons

The element iron is in group 8, and therefore has two or three apparent valence electrons.

Electron shells are labeled K, L, M, N, O, P, and Q or simply 1 to 7; starting with the shell closest to the nucleus and moving out. Each electron shell can hold a fixed, maximum number of electrons: the K shell holds a maximum of two electrons, the L shell holds eight electrons, the M shell holds eighteen electrons and the N shell holds a maximum of thirty-two electrons. Theoretically, the O Shell could contain fifty electrons and the P shell could contain seventy-two electrons, but no naturally occurring element has more than thirty-two electrons in any single shell.

The maximum number of valence electrons for an atom is eight.

There are two lines of elements listed below the main table on the periodic chart, the lanthanides and actinides. All lanthanides belong in Period 6, Group 3. Actinides belong in Period 7, Group 3. These elements are known as inner transition metals.

Any of the fundamental negatively charged particles in the outermost area of atoms that participate in the creation of chemical bonds are referred to as valence electrons. Changes in the atomic structure are confined to the outermost, or valence, electrons regardless of the kind of chemical connection (ionic, covalent, or metallic) between atoms. They are less strongly attracted to the positive atomic nucleus than the inner electrons and can thus be shared or transferred during the bonding process with nearby atoms. In metals and semiconductors, valence electrons are also involved in the conduction of electric current.

What Are Valence Electrons?

The number of electrons an atom needs loses or gain to reach the octet or ensure stability is known as valence. Valence electrons are electrons in the outer shells that are not filled.

Because valence electrons have higher energy than electrons in inner orbits, they are involved in the majority of chemical processes. They assist us in determining the chemical properties of an element, such as its valency or how it forms bonds with other elements. It also tells us how easily atoms can make bonds, how many unpaired electrons there are, and how many atoms may participate.

Characteristics of Valence Electrons:

  1. The valence electron exists exclusively in the outermost electron shell of the main group elements.
  2. In the inner shell of a transition metal, a valence electron can exist.
  3. Chemically, an atom with a closed shell of valence electrons is usually inert.
  4. The electrical conductivity of an element is also determined by its valence electrons. A metal, a non-metal, or a metalloid, depending on the nature of the elements.

Determination of Valence Electrons:

The number of valence electrons in neutral atoms is equal to the atom’s main group number.

Number of valence electrons = Main group number (neutral atoms)

The main group number of an element can be found in its periodic table column. Carbon, for instance, belongs to group 4 and has four valence electrons. Oxygen belongs to group 6 and has a valence electron count of 6.

Electron Dot Diagrams

An electron dot diagram is a representation of an atom’s valence electrons that employs dots to surround the element’s symbol. The number of dots corresponds to the atom’s valence electrons. With no more than two dots on each side, these dots are positioned to the right and left, above and below the symbol.

  1. To begin, add the individual valencies of each atom to get the total amount of valence electrons in the molecule.
  2. If the molecule is an anion, extra electrons (Number of electrons added = magnitude of negative charge) are added to the Lewis dot structure.
  3. When considering cationic compounds, electrons are removed from the overall count to compensate for the positive charge.
  4. The molecule’s or ion’s core atom is comprised of the least electronegative atom.
  5. Single bonds are now used to connect the atoms.
  6. Each atom in the molecule now has a lone pair of electrons assigned to it. The most electronegative atoms are usually assigned the lone pairs first.
  7. If every atom does not have an octet configuration after the lone pairs have been allocated, a double or triple bond must be drawn to fulfill the octet valency of each atom.
  8. To meet the octet rule for two atoms, a lone pair can be changed into a bond pair if necessary.
  1. The valence shell of an oxygen atom includes six electrons.
  2. Four of the valence electrons are in lone pairs, meaning that in order to achieve an octet configuration, the oxygen atom must engage in two single bonds or one double bond.
  3. Because an O2 molecule has just two oxygen atoms, the atoms form a double bond, resulting in the Lewis electron dot structure shown below.

Electron Dot Diagram of CO2

Finding Valence Electrons for All Elements Except Transition Metals

Each of the periodic table’s squares. Determine the atomic number, group, and a periodic number of oxygen, for example. Elements with comparable chemical characteristics are grouped together in the periodic table. The number of electron shells possessed by atoms of the elements in that row is measured in periods. Period 2 and Group 16 include oxygen.

The following rule should be used: If an element is not a transition metal, the number of valence electrons increases as the period progresses from left to right. With one valence electron, a new period begins. According to this rule, group 1 elements have one valence electron, group 2 elements have two valence electrons, group 13 elements have three valence electrons, group 14 elements have four valence electrons, and so on.

Valence Electrons and Reactivity

The most reactive metallic elements, such as sodium and potassium, are found in group 1. As a result, group 1 elements have single valence shell electrons that can readily be lost to produce a positive ion. As a result, it only has one electron to lose, making it easier to connect and more reactive. Because the metals in group 2 have two valence electrons in their valence shell, they must lose two valence electrons to produce a positive metal ion. Losing two electrons is more difficult than losing one. As a result, they are less reactive, and these metals are more durable than group 1 elements.

The reactivity of metals tends to grow as they progress through each group. As the valence electrons become less bonded to the nucleus, they will be more easily withdrawn, and as the number of shells grows by one down the group, the atomic size will increase as well.

To create their link, nonmetals must attract electrons towards themselves. It may share electrons with an adjacent atom to make a covalent bond, or it could take one electron away to form an ionic bond. As a result, halogens are the most reactive nonmetals, as they only require one electron to form bonds. To create a covalent link, they either remove an electron from another atom or share an electron from another storm. Because the valence electrons are at progressively higher energies in groups, the nonmetal’s reactivity reduces because the atoms are unable to gain stability by obtaining electrons.


An atom’s electrons are grouped in distinct orbits. According to the Bohr-Bury system, an atom’s outermost shell can hold up to 8 electrons. Furthermore, atoms with a totally filled outermost shell have little chemical activity, implying that their valency is zero. It also indicates that they are inactive substances. Helium has two electrons in its outermost shell, while the other inert elements have atoms with eight electrons in their outermost shells. An octet is defined as an outermost shell with eight electrons. As a result, atoms would react to form an octet in the outermost shell. By sharing, gaining, or losing electrons, the octet is formed. The valency of an element is determined by the number of electrons acquired, lost, or shared to complete the octet in the outermost shell.

A chemical reaction involves either electron removal, electron addition, or electron sharing. The path a specific element will take depends on where the electrons are in the atom and how many there are.

Electron Configurations of Second-Period Elements

Element Name Symbol Atomic Number Electron Configuration
Lithium Li 3 1s 2 2s 1
Beryllium Be 4 1s 2 2s 2
Boron B 5 1s 2 2s 2 2p 1
Carbon C 6 1s 2 2s 2 2p 2
Nitrogen N 7 1s 2 2s 2 2p 3
Oxygen O 8 1s 2 2s 2 2p 4
Fluorine F 9 1s 2 2s 2 2p 5
Neon Ne 10 1s 2 2s 2 2p 6

In the study of chemical reactivity, we will find that the electrons in the outermost principal energy level are very important and so they are given a special name. Valence electrons are the electrons in the highest occupied principal energy level of an atom. In the second period elements listed above, the two electrons in the 1 s sublevel are called inner-shell electrons and are not involved directly in the element’s reactivity or in the formation of compounds. Lithium has a single electron in the second principal energy level and so we say that lithium has one valence electron. Beryllium has two valence electrons. How many valence electrons does boron have? You must recognize that the second principal energy level consists of both the 2 s and the 2 p sublevels and so the answer is three. In fact, the number of valence electrons goes up by one for each step across a period until the last element is reached. Neon, with its configuration ending in s 2 p 6 , has eight valence electrons.

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How to find valence electrons

Origin of valence electron

Words nearby valence electron


What are valence electrons?

A valence electron is a negatively charged particle, located in the outermost shell of an atom, that can be transferred to or shared with another atom.

Valence (or valency) is an atom or group of atoms’ ability to chemically unite with other atoms or groups. Electrons are negatively charged subatomic particles surrounding the nucleus of an atom in shells. Valence electrons, then, are electrons in the outermost shell of the atom that determine an atom’s or group’s ability to bond with others.

In chemistry, a group refers to two or more atoms that are specifically arranged. Groups are also called radicals. Free radicals are unstable, highly reactive atoms or molecules that have unpaired valence electrons.

Valence electrons, bonding, and chemistry

Atoms may be teeny-tiny, but they have a lot going on beneath the surface. During the early 1900s, Gilbert N. Lewis (an American chemist and professor at University of California, Berkeley) significantly contributed to our understanding of valence electrons.

Some fundamentals: atoms are made up of neutrons, protons, and electrons. The nucleus (or the center of an atom) consists of neutrons and protons. Electrons surround the nucleus in shells. The shell closest to the nucleus can hold two electrons. The second shell can hold up to eight electrons, the third up to 18. (Different elements have different numbers of shells, each shell can hold only a fixed number of electrons, and there’s a formulaic way to determine that number).

Atoms—perhaps not unlike people?!—have one primary goal: to become stable. When the outer shell around an atom is filled with valence electrons, the atom is stable and doesn’t need to interact with other atoms to find stability. This is why elements like neon and argon don’t really react with other elements (because their outermost shell is naturally full with eight valence electrons).

So, what do atoms do if their outermost shell isn’t completely filled with valence electrons? They bond with other unstable atoms! There are two basic kinds of bonds:

The first kind is called a covalent bond. Covalent bonds happen when two atoms bond together by sharing valence electrons. One example of a covalent bond is a hydrogen bond (or H₂). A single hydrogen atom only has one outer shell and one valence electron. Remember, the first shell can hold two electrons, so hydrogen is naturally unstable. To fix this, a hydrogen atom will share a valence electron from another hydrogen atom so they both find stability.

The second kind of bond is an ionic bond. When one atom gains a valence electron while another atom loses a valence electron, that’s called an ionic bond. Ionic bonds tend to be stronger than covalent bonds. Sodium fluoride (NaF) is a common example of a compound formed by an ionic bond. Sodium has only one valence electron in its third shell while fluorine has seven valence electrons in its second shell (sodium doesn’t have a third shell). When they bond, sodium “gives” its valence electron to fluorine so they both can have eight valence electrons in their outer shells and be stable.

Did you know . ?

When you brush your teeth in the morning, give thanks to sodium fluoride—and its shared valence electrons—in your toothpaste for fighting cavities. And, the next time you see a rocket soaring into space, know that there’s liquid hydrogen bonds fueling it.

What are real-life examples of valence electrons?

Here is a video explaining and visualizing how valence electrons work. They are tough concept, we know!

“How are you feeling?”
“Like I lost a valence electron”
“. ”

— Hales🌱 (@alll_hale) April 24, 2019

How to find valence electrons

Electrons exist in orbitals around a nucleus. These orbitals and the energy needed to remove each of these electrons from the atom are set by quantum mechanics. Each of these orbitals serves to create a shell of electrons in the atom. Valence electrons are the electrons orbiting the nucleus in the outermost atomic shell of an atom. Electrons that are closer to the nucleus are in filled orbitals and are called core electrons. Valence electrons are the farthest from the positive charge (the protons) and thus tend to be easier to remove than core electrons; this means that it takes them less energy to move far away from the atom. This difference comes from the electric force being an inverse square law. In addition, core electrons in the inner shells have lower energy levels than the valence electrons occupying the outer shell. This means that electrons in the inner shells can absorb bits of energy and move (jump) to the valence electron shell.


Valence electrons and chemical reactions

In chemical reactions, the electrons can even break free from the valence shell. This can be to create an ionic bond or to become an ion. When an electron leaves a neutral atom, it loses a negative charge and turns into a positively charged ion. For example, sodium (Na) has one electron in it’s outer shell. Thus it wants to lose a single electron and become an Na + ion. An atom can also gain an electron (usually to fill it’s valence shell) and turn into a negatively charged ion. This can be seen with Chlorine, which in it’s neutral state is missing one electron in it’s valence electron shell. Thus, it wants to pick up an electron and become a Cl – ion. [2]

Noble gases are elements that have a full valence shell, meaning that the outer shell is completely filled with electrons. Noble gases neither want to gain or lose an electron, which means they tend to be chemically inert (unreactive). In general, atoms want to have full valence electron shells. This is why atoms, and also chemical compounds, lose or gain electrons to become ions, and also why they form ionic and covalent bonds.

Valence electrons and chemical bonding

How to find valence electrons

In both ionic and covalent bonding, it is the valence electrons that participate these chemical bonds. [2] In single covalent bonds, typically both atoms in the bond contribute one valence electron each in order to form a shared electron pair. An example is seen in figure 2 where a strong sigma bond (σ bond) is formed. Valence electrons are also used to form double and triple bonds, which have valence electrons configured in pi bonds (π bonds). [4]

In ionic bonding, valence electrons are completely transferred between atoms. It is a type of chemical bond that generates two oppositely charged ions, one anion and one cation. Ionic bonding is observed because metals have few electrons in their valence orbitals and nonmetals almost have 8 electrons in their valence shells. Metals lose their valence electrons and become more stable by satisfying the octet rule. Similarly, nonmetals will readily accept electrons to achieve a noble gas configuration. [4]

For more information about valence electrons, core electrons and how they related to chemical reactions please see UC Davis’s chem wiki.

For Further Reading


  1. ↑ This image was created by part of the Energy Education team.
  2. ↑ 2.02.1 “Valence electrons and open valences.” Chemistry LibreTexts, 2019. [Online]. Available: [Accessed: May 15, 2021]
  3. ↑ “Illustrated Glossary of Organic Chemistry.” UCLA College. Online. Available:

Authors and Editors

Allison Campbell, Jordan Hanania, Amanda Musgrove, Jasdeep Toor, Dayna Wiebe, Jason Donev
Last updated: December 20, 2021
Get Citation

A valence electron is an electron in an outer shell of an atom that can participate in forming chemical bonds with other atoms. In a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

The presence of valence electrons can determine the element's chemical properties and whether it may bond with other elements. For a main group element, a valence electron can only be in the outermost electron shell. However, in a transition metal, a valence electron can also be in an inner shell.

Corrosionpedia Explains Valence Electron

Valence electrons are the electrons in the outermost electron shell of an atom. The number of electrons in an atom's outermost valence shell governs its bonding behavior. That is why elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table. Within each group of metals, reactivity increases when moving downward on the table. Within each group of nonmetals, reactivity decreases with lower positions on the table.

Elements are most stable when they have all eight valence electrons. This is called the octet rule. The only elements that have this electron configuration are the noble gases, thereby they are inert. All other elements gain, lose or share electrons in order to achieve a full set of valence electrons. Non-metals have a strong pull on their valence electrons, so they tend to gain electrons in order to gain stability and become more like a noble gas. Because metals have loose valence electrons, they always lose electrons in order to gain stability. When a metal loses electrons, it has more protons than electrons and is therefore a positive ion.

Valence electrons are also responsible for the electrical conductivity of an element; as a result, an element may be classified as a metal, nonmetal or semiconductor (metalloid). A metal is an element with high electrical conductivity or malleability when in the solid state. A nonmetallic element has low electrical conductivity; it acts as an insulator. A semiconductor has an electrical conductivity that is intermediate between that of a metal and that of a nonmetal.