Question

1. which element is not reactive? (1pts)

silicon
vanadium
barium
helium

1. using the periodic table, predict which compound is molecular: (1pts)

mgo
fes
naoh
sio₂

Explanation:

For Question 23:

Noble gases have full valence electron shells, making them non-reactive. Helium is a noble gas, while the other options are reactive metals or a metalloid.

For Question 24:

Molecular compounds form between nonmetals (or metalloids and nonmetals) with covalent bonds. Ionic compounds form between metals and nonmetals. $\text{SiO}_2$ is made of metalloid Si and nonmetal O, forming a covalent network molecular compound; the others are ionic compounds.

Answer:

1. $\square$ silicon

$\square$ vanadium
$\square$ barium
$\square$ helium

1. $\square$ MgO

$\square$ FeS
$\square$ NaOH
$\square$ SiO$_2$