Q37 of 203 Page 152

The atomic number of an element E is 16. The number of electrons in ion E2- will be:

as the symbol suggests the gain of two electrons, the atomic number is likely to be 18.

A particle X has 17 protons, 18 neutrons and 18 electrons. This particle is most likely to be:

An element which can exhibit valencies of 2, 4 and 6 can be:

The cation of an element has:

Two elements X and Y have valencies of 5 and 3, and 3 and 2, respectively. The elements X and Y are most likely to be respectively: