Ionic Bonding Flashcards

All 18 cards in this deck

What is an ion?

An atom or group of atoms with a positive or negative charge.

What is a cation and what is an anion?

A cation is a positive ion (an atom that has lost electrons); an anion is a negative ion (an atom that has gained electrons).

What charge do the ions of elements in groups 1, 2, 6 and 7 have?

Group 1: $1+$, group 2: $2+$, group 6: $2-$, group 7: $1-$.

A chlorine atom has the electronic configuration 2.8.7. What is the electronic configuration of the chloride ion, $\mathrm{Cl^-}$?

2.8.8 — it has gained one electron, giving a full outer shell.

What are the steps to find the numbers of protons, neutrons and electrons in a simple ion?

e.g. a fluoride ion $\mathrm{F^-}$, atomic number 9, mass number 19

1. Protons = atomic number = 9
2. Neutrons = mass number − atomic number = 19 − 9 = 10
3. Electrons = protons + 1 for each negative charge (− 1 for each positive charge) = 9 + 1 = 10

True or false? When an atom forms an ion, its number of protons changes.

False. Only electrons are lost or gained; the number of protons (and the mass number) stays the same.

How is an ionic bond formed?

e.g. sodium reacting with chlorine

By transfer of electrons from a metal atom to a non-metal atom, forming oppositely charged ions that attract each other.

e.g. Na loses 1 electron to Cl, giving $\mathrm{Na^+}$ and $\mathrm{Cl^-}$.

Describe the structure of an ionic compound.

A giant lattice: a regular arrangement of ions held together by strong electrostatic forces (ionic bonds) between oppositely charged ions.

What are the steps to draw a dot and cross diagram for an ionic compound?

e.g. sodium chloride, NaCl

1. Draw the outer shell electrons of each atom: Na has 1 dot, Cl has 7 crosses
2. Transfer the metal's outer electrons to the non-metal so both have full outer shells
3. Draw each ion in brackets with its charge: $\mathrm{Na^+}$ (2.8) and $\mathrm{Cl^-}$ (2.8.8)

In a dot and cross diagram, why are dots used for some electrons and crosses for others?

To show which atom each electron came from, so the transfer of electrons can be seen.

Why do atoms of groups 1, 2, 6 and 7 lose or gain electrons when forming ions?

To gain a full (stable) outer shell, like that of a noble gas.

True or false? In ionic bonding, electrons are shared between the atoms.

False. Electrons are transferred from the metal atom to the non-metal atom; sharing happens in covalent bonding.

What does the ending –ate tell you about a compound?

It contains a compound ion that includes oxygen.

e.g. copper sulfate contains $\mathrm{SO_4^{2-}}$.

Give the formulae of the hydroxide, nitrate, carbonate and sulfate ions.

$\mathrm{OH^-}$, $\mathrm{NO_3^-}$, $\mathrm{CO_3^{2-}}$, $\mathrm{SO_4^{2-}}$.

What are the steps to deduce the formula of an ionic compound from its ions?

e.g. $\mathrm{Mg^{2+}}$ and $\mathrm{Cl^-}$

1. Write the two ions with their charges: $\mathrm{Mg^{2+}}$, $\mathrm{Cl^-}$
2. Choose numbers of each ion so the charges cancel to zero: one $\mathrm{Mg^{2+}}$ to two $\mathrm{Cl^-}$
3. Write the formula without charges: $\mathrm{MgCl_2}$

When do you need brackets in the formula of an ionic compound?

e.g. $\mathrm{Ca^{2+}}$ with $\mathrm{NO_3^-}$

When more than one compound ion is needed, so the number applies to the whole ion.

e.g. $\mathrm{Ca(NO_3)_2}$.

True or false? The formula of calcium carbonate is $\mathrm{Ca(CO_3)_2}$.

False. It is $\mathrm{CaCO_3}$, because $\mathrm{Ca^{2+}}$ and $\mathrm{CO_3^{2-}}$ balance one to one.

True or false? The formula of an ionic compound has no overall charge, because the total positive charge of the cations equals the total negative charge of the anions.

True. The ions combine in the ratio that makes the compound electrically neutral, e.g. $\mathrm{Mg^{2+}}$ and $\mathrm{Cl^-}$ give $\mathrm{MgCl_2}$.