Which element has 7 valence electrons?

a nitrogen (n)

b neon (ne)

c lithium (li)

d chlorine (ci)

Can someone explain to me how to do this problem ?

The specific heat of silver is 0.057 calories/gram°c. if 10.0 grams of silver were heated and the temperature of the sample changed by 20.0°c, how many calories of heat energy were absorbed by the sample?

The electronic structure or chlorine is 2.8.7 what is the electronic structure of fluorine?