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.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current