Because going down a column you are jumping up to the next higher main energy level (n) and each energy level is further out from the nucleus
All of the the answers are are correct but a fume hood is more for if you are dealing with chemicals that can produce fumes the are deadly to people
A metalloid is a metal and a nonmetal
If its sodium it would have 11 electrons
Answer : The formula unit of Sr & Cl is
and the formula unit of Al & S is 
Explanation :
Formula unit : it is defined as the lowest number ratio of ions of an elements in an ionic compound or covalent compound.
For the formula unit of Sr & Cl, two chloride ions
are needed to neutralize the one strontium ion
.
For the formula unit of Al & S, three sulfide ions
are needed to neutralize the two aluminium ion
.
The formula unit of
and
are shown below.