What is the correct way to represent the ionic compound sodium fluoride?

(Na)+. (Fl)-

Explanation:

Na=2.8.1

Fl=2.7

Sodium will give fluorine its one atom to be a cation + with a configuration of 2.8 while fluorine will be a anion - with a configuration of 2.8

I don't know how to add a picture, so I might not explain this well.

Explanation: You put Na in the first box. Then you put F in the center of the second box because it gained one electron from Na. Then in the third box you put Na [+] because it lost one electron so it's now an cation(has a positive charge) because it lost a valence electron. In the last box you would put F [-] because it gained one electron so it's now an anion( has a negative charge) because it gained a valence electron. F now has 8 valence electrons and Na has 8 as well therefore they're both balanced.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

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.