SCRIE FORMULA ŞI DENUMEŞTE SUBSTANŢA

10. 1 atom azot şi 3 atomi de
hidrogen
11. 2 atomi de hidrogen, 1 atom de cabon şi 3 atomi de
oxigen

Totul este greu înainte de

a deveni ușor

12. 1 atom de carbon şi 2 atomi de oxigen

13. 1 atom de calciu şi 1 grupare
carbonat
14. Pb (II) și 1 grupare carbonat
15. Co (II) și o grupare fosfat
16. Arsen și un radical sulfură

Here's what I get  

Explanation:

10. NH₃, ammonia

11. H₂CO₃, carbonic acid

12. CO₂, carbon dioxide

13. CaCO₃, calcium carbonate

14. PbCO₃ lead(II) carbonate  

15. Co₃(PO₄)₂, cobalt(II) phosphate

16. As₂S₃, arsenic(III) sulfide.

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.  

that's what i got you can count the number of atoms