Ions and Valence Electrons

Ionic Compounds

• Ion: when an atom gains or loses a valence electron (gaining a + or - charge) to complete its outer energy level.

• Ionic Compound: compound between a metal and a nonmetal where one atom gains a valence electron and the other atom loses a valence electron.

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​Ionic Compounds

Multiple Choice

An ion is formed when an atom gains or loses an ______________.

• Proton

• Neutron

• Electron

• Nucleus

Multiple Choice

An Ionic Compound is formed between what two types of elements?

• Metal and Metal

• Metal and Nonmetal

• Nonmetal and Nonmetal

• Metal and Metalloid

In an Ionic Compound:

• The metals lose and electron and gain a positive charge. We call these positive ions cations.

• The nonmetals receive an electron and gain a negative charge. We call these negative ions anions. ​

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Multiple Choice

In an ionic compound - metals _____ electrons, giving them a _____ charge. We call these types of ions _____.

• Lose / Negative / Cation

• Lose / Positive / Cation

• Gain / Negative / Anion

• Gain / Positive / Anion

Multiple Choice

In an ionic compound - nonmetals _____ electrons, giving them a _____ charge. We call these types of ions _____.

• Lose / Negative / Cation

• Lose / Positive / Cation

• Gain / Negative / Anion

• Gain / Positive / Anion

The group number determines the number of valence electrons.

• Group 1 - 1 ve

• Group 2 - 2 ve

• Group 13 - 3 ve

• Group 14 - 4 ve

• Group 15 - 5 ve

• Group 16 - 6 ve

• ​Group 17 - 7 ve

• Group 18 - 8 ve​

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​Determining Valence Electrons

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We use the number of valence electrons to determine the ionic charge of the group. According to the Octet Rule elements want to have a full outer energy level (8 e-) because of this elements in different groups form ions.

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Valence Electrons = Ionic Charge

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• ​Group 1 = +1

• Group 2 = +2​

• Group 13 = +3​

• Group 14 = +/- 4​

• Group 15 = -3

• Group 16 = -2

• Group 17 = -1

• Group 18 = 0​

Multiple Choice

How many valence electrons does Boron (B) have?

• 5

• 13

• 3

• 11

Multiple Choice

How many valence electrons does Argon (Ar) have?

• 18

• 8

• 40

• 22

Multiple Choice

How many electrons does Sodium (Na) want to gain or lose and what ionic charge is created from this?

• 1 / +1

• 1 / -1

• 11 / +1

• 11 / -1

Multiple Choice

How many electrons does Chlorine (Cl) want to gain or lose and what ionic charge is created from this?

• 1 / +1

• 1 / -1

• 11 / +1

• 11 / -1

Ionic Bonding

How are Ionic Compounds formed?

In an ionic compound the metal will give it's low number of valence electrons to a nonmetal, because of this the metal who has lost electrons has a positive charge and the nonmetal that has gained electrons has a negative charge and they are attracted to one another creating a new compound.

​Writing Ionic Formulas

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• After identifying the reaction as an ionic compound between a metal and a nonmetal to write the formula:

  • Identify the ionic charge / oxidation number (charge of each element) 

  • Drop and swap the charges writing them as subscripts. 

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• If the charges are equal and opposite (Neutral - Na +1, Cl -1; Ca +2, O -2; Al +3, P -3) there is no subscripts required for that reaction since the ratio would be 1:1 / 2:2 / 3:3.

​If the ionic charges are not equal and opposite we use the drop and swap method to identify the number of subscripts for each element.

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Ionic Bonding:

Drop + Swap​

Multiple Choice

Creating an ionic compound:

What are the ionic charges for Calcium and Cl?

• Ca +1

  Cl -2

• Ca -1

  Cl +2

• Ca -2

  Cl -2

• Ca +2

  Cl -1

Multiple Choice

Creating an ionic compound:

Are the charges of Calcium and Chlorine equal and opposite?

• Yes

• No

Multiple Choice

Creating an ionic compound:

What formula is created when Calcium and Chlorine form an ionic bond?

• CaCl

• CaCl₂

• Ca₂Cl

• Ca₂Cl