Quantitative Chemistry: Formula of Ionic Compounds (DONE)

Question 1

This deck of cards is to help you determine the formula of an ionic compound using the charges on ions.

Answer 1

This deck of cards is to help you determine the formula of an ionic compound using the charges on ions.

Question 2

In an _____ compound, the charges on the ions have to _____ _____ to leave an overall charge of zero.

Answer 2

In an ionic compound, the charges on the ions have to cancel out to leave an overall charge of zero.

Question 3

What must happen for an ionic compound to have an overall charge of zero?

Answer 3

For an ionic compound to have an overall charge of zero the charges on the ions must cancel out.

Question 4

Can ionic compounds have an overall charge?

Answer 4

Ionic compounds cannot have an overall charge.

(and if they do then they aren’t an ionic compound)

Question 5

What is the formula of the ionic compound sodium chloride?

Sodium = Na^+
Chloride = Cl^-

(You will be given the charges on any ions you need in an exam question.)

Answer 5

Sodium ion has a single positive charge and the chloride ion has a single negative charge this means that one sodium ion can cancel out the charge on one chloride ion so the formula of sodium chloride is:

NaCl

Hypothetical:
If we had two sodium ions then the compound would have an overall one plus charge NaCl^3 And this is NOT allowed.

Question 6

What is the formula of the ionic compound sodium oxide?

Sodium = Na^+
Oxide = O^2-

(You will be given the charges on any ions you need in an exam question.)

Answer 6

Remember that the charges have to cancel so this means that we need two sodium ions to cancel out the charge on one oxide ion so the formula is:

Na↓2↓O

Question 7

What is the formula of the ionic compound magnesium iodide?

Magnesium = Mg^2+
Iodide = I^-

(You will be given the charges on any ions you need in an exam question.)

Answer 7

The magnesium ion has a two plus charge and the iodide ion has a one minus charge. In this compound we need two iodide ions to cancel out the two plus charge on the magnesium ion so the formula is:
MgI↓2

Question 8

What is the formula of the ionic compound lithium carbonate?

Lithium = Li^+
Carbonate = CO↓3^2-

(You will be given the charges on any ions you need in an exam question.)

Answer 8

The lithium ion has a one plus charge and the carbonate ion has a charge of two minus so this means that we need two lithium ions to cancel out the charge on one carbonate ion so the formula of this compound is:

Li↓2CO↓3

Question 9

What is the formula of the ionic compound calcium hydroxide?

Calcium = Ca^2+
Hydroxide = OH^-

(You will be given the charges on any ions you need in an exam question.)

Answer 9

The calcium ion has a two plus charge and the hydroxide ion has a one minus charge so we need two hydroxide ions to cancel out the charge on one calcium ion. So the formula of calcium hydroxide is:

Ca(OH)↓2

We must place brackets and then put the two below it because if we don’t and then place the two directly to the right of the H then that’ll mean we have two hydrogen atoms rather than two hydroxide ions. The little two shows us we have two hydroxide ions.

Question 10

What is the formula of the ionic compound magnesium nitrate?

Magnesium = Mg^2+
Nitrate = NO↓3^-

(You will be given the charges on any ions you need in an exam question.)

Answer 10

Mg(NO↓3)↓2