Hi :) anyone able to help with qn 4 & explain too? Thank you:)!!

Please see the attached picture.

Explanation:

Magnesium chloride involves a metal and a non-metal so it is an ionic bonding. (Involves transfer of electrons not sharing)

① Write down the electronic configuration of magnesium and chlorine.

✓ You have written it down correctly :)

② Write down the charges of the magnesium and chlorine ion. You can do this with the help of the periodic table. Since magnesium is in group 2, its charge is 2+ and since chlorine is in group 7, its charge is -1.

For better understanding, what we are trying to achieve here is a stable octet or duplet structure. To do this, the atoms have to gain or lose electrons. For magnesium, it could either lose 2 electrons or gain 6 electrons to ensure that there is 8 valence electrons. But it is easier to lose 2 electrons (takes lesser energy) thus the charge is +2. (To remember better, magnesium gives away 2 electrons so it is a "positive act" and hence its charge is positive 2. Don't take that literally though ^^)

③ Write down the formula of the compound and that will help you know how many atoms of each element are involved. (MgCl₂ ➪ 1 Mg atom and 2 Cl atoms)

④ Draw the dot and cross diagram.

☆ Since the 2 electrons in the 3rd shell of magnesium atom have been given away, the last shell is empty so there is only 2 shells left. ( Draw 2 circles only)

Chlorine atom gains another electron hence the 2nd shell becomes full (stable) and thus, you still have to draw 2 circles.

•It is encouraged to include the key to explain your symbols such as the dots and crosses.

the correct answer is:

a. formation of precipitation