Please help me urgently is for a test and I need to do this homework and i don’t understand

Explanation

TIP:

group 1= 1 valence

group 2= 2valence

group 3- 12 vary depending on the charge

group 13= 3 valence

group 14= 4 valence

group 15= 5 valence

group 16= 6 valence

group 17= 7 valence

group 18= 8 valence (a full shell) they don't bond they're noble gases

This should tell u the valences :) it says the group on the top of your picture just look at the small text.

The dot structure:

1. write the symbol for example Zinc is Zn.

Zinc has 2 valence electrons (you can figure out the valence of transition metals by doing the electron config but that's painful and annoying so i'm just going to tell u it)

Imagine the symbol Zn has a border on it like a square. each side can ONLY have 2 dots MAXIMUM!! therefore its dot structure will look like:

:Zn   (it doesn't matter what side you put them on, if it were 3 valence just add a lonely dot on an empty side and so on so forth)  

Hope i helped

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.