Answer
$1.\ A=28, 14\ protons,0\ charge\\
2.\ Z=16, 16\ protons,18\ electrons,16\ neutrons\\
3.\ Z=29,A=63,29\ protons,27\ electrons\\
4.\ P, A=31,15\ protons, 0\ charge $
Work Step by Step
1. An atomic number of 14 implies that there are 14 protons and mass number is determined by adding number of protons and neutrons. Thus, the mass number is A= 14+14 = 28. An atom is electrically neutral so it's charge is 0.
2. Sulphur's atomic number is 16 which means that there are 16 protons and a charge of -2 suggests a gain of 2 electrons therefore this ion has 18 electrons. Number of neutrons is found by formula $N=A-Z$. Therefore, there are 32-16 = 16 electrons.
3. Copper's atomic number is 29 implies 29 number of protons.A harge of +2 implies loss of 2 electrons therefore, this ion has 27 electrons. The mass number is determined by adding the number of protons and neutrons. Thus the mass number is $A=29+34=63$
4. A atomic number of 15 implies 15 protons and element is Phosphorus($P$) . The mass number is sum of protons and neutrons, $A=15+16=31$. Since there are equal amount of proton and electron, total charge is 0 and it's a neutral atom.
