CHEMISTRY i really need help cuz it depends if i pass 4 the 3rd quarter...Thanx?

[Alcus]

16 , 17, nd 18 O (superscripts in front of O) all have the same number of? electron, but a different # of protons
protons, but a dif. # of electrons
neutrons, but a dif. # of protons
protons, but a dif # of neutrons

which element can be brittle or soft in the solid phase and is a poor conductor of heat and electricity?
1)strontium
2)sulfur
3)calcium
4)copper