Five atoms are labelled from A to E.
| Atoms |
Mass No. |
Atomic No. |
| A |
40 |
20 |
| B |
19 |
9 |
| C |
7 |
3 |
| D |
16 |
8 |
| E |
14 |
7 |
(a) Which one of these atoms:
(i) contains 7 protons,
(ii) has an electronic configuration 2, 7?
(b) Write down the formula of the compound formed between C and D.
(c) predict which are:
(i) metals,
(ii) non-metals?
