Question

Question #d0ea6

Answer 1

NaCl

Explanation:

Na has a valence of +1, Chlorine -1. Hence they must be present in a 1:1 ratio.

Answer 2

NaCl

Explanation:

Sodium (Na) is a metal.
Chlorine (Cl) is a non-metal.

When metals and non-metals combine, they form an ionic compound. Since sodium is in the first group on the table, the Alkali Metals, we know it has a single electron in it's outer shell (valence electron), so it only holds on to that electron loosely, easily letting it go to be left with the full shell below. This leaves it with a positive charge (losing a negative electron makes it positive) so it becomes a sodium ion: `Na^+`.

Chlorine has an almost full valence shell, and will pull in another electron (from, say sodium) to complete it's outer electron shell, leaving it with a negative charge (from an extra negative electron). It becomes a chlroide ion: `Cl^-`.

Since one is positive and the other is negative, they attract each other. And since they both have a charge of 1, then one of each will balance out:

`Na^+ + Cl^(-) = NaCl`

If the question asked about another element, such as magnesium instead of sodium, we would have to do a tiny bit more work. Magnesium has 2 valence electrons, so if it looses them it becomes an ion of charge 2: `Mg^(2+)`

`Mg^(2+)` would have to attract 2 `Cl^-` ions to neutralize it, so the final ionic compound would be `MgCl_2`.