Predict the formula of the stable binary compounds that would be formed by the combination of the following pairs of elements.
a.Lithium and oxygen
b. Magnesium and nitrogen
c. Aluminium and iodine
d. Silicon and oxygen
e. Phosphorus and fluorine
f. Element `71` and fluorine

Explanation

a. Lithium is an alkali metal `(Group 1)`. It has only one electron in the valence shell, therefore, its valence is `1`.Oxygen is a group `16` element with a valence of `2`. Therefore, formula of the compound formed would be `Li_(2)O` (lithium oxide).
b.Magnesium is an alkali earth metal `(Group 2)`. hence has a valence is `2`.Nitrogen is a group `15` element with a valence of `8-5=3`. Thus, the formula of the compound formed would be `Mg_(3)N_(2)` (magnesium nitride).
c. Aluminium is group `13` elements with a valence of `3` while iodine is a halogen `(group 17)` with a valence of `1`. Therefore, the formula of the compound formed be `AII_(3)`(Aluminium iodide.).
d. Silicon is group `14` elements with a valence of `4` while oxygen is a `(group 16)` with a valence of `(8-6=2)`. Hence, the formula of the compound formed be `SiO_(2)`(silicon dioxide).
e. Phosphorus is a group `15` element with a valence of `3` or `5` while flurine is group `17` element with a valence of `1`. Hence, the formula of the compound formed would be `PF_(3)` or `PF_(5)`.
f. Element with atomic number `71` is a lanthanoid called lutetium `(Lu)`. Its common valence is `3`. Fluorine is a group `17` (halogen) element with a valence of `1`. Therefore, the formula of the compound formed would be `LuF_(3)`(lutetium fluoride).