1. The energy required to remove one electron from an ion carrying a -1 charge is called...

Select one:
1. second electron affinity.
2. second ionization
energy.
3. first electron affinity.
4. first ionization energy

2. Sodium chloride is an ionic compound with the basic formula NaCI.
Which option describes the nature of sodium chloride?

1. It is crystal made from sodium and chloride atoms in 1:1 ratio
2. It is made up of molecules, each of which has one sodium and one chloride atom.
3. It is a crystal made from an inner core of sodium Atoms surrounding by chlorine atoms.
4. It is made up of individual sodium and chlorine atoms that are not connected to each other.

3. A sample of lithium sulfide has a twice as many lithium atoms as it had sulfur atoms.
If sulfur ions carry the charge of 2-, what is the charge of lithium ions?