If a neutral copper atom becomes an ion that has a charge of 2+, how many electrons does the resulting ion have? a31
b27
c29
d28

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock