Katherine dissolves a tablespoon of salt into a glass of water, and watches as it disappears. she remembers from science class that sodium has an atomic number of 11, and chlorine of 17. as a result, she knows that in solution, when the molecules separate, sodium will be a

When table salt, which is chemically sodium chloride is added to water, the salt readily dissolves in the water. Sodium chloride being an ionic compound ionizes into sodium ion, Naand chloride, Cl.Sodium has an atomic number 11 and chlorine has an atomic number of 17.

Na-(2,8,1) can readily lose the outermost electron in order get a stable octet configuration on the valence shell. So, sodium forms a cation

Cl-(2,8,7) accepts an electron to complete the octet. So, chlorine forms an anion.

Sodium will form a cation and chlorine an anion when NaCl is dissolved in water.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6