Formula unit represents the simplest ratio of elements in a of an ionic compound.
a crystal is made up of
there are two magnesium ions for every two sulfide ions in magnesium sulfide. the ratio of mg to s in the formula unit is .

gravity causes stares to cluster i think so

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

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

it would be d. henry moseley

hope this !

and sorry if i'm late. have a good rest of your day! : d