The statement which describes a physical property of the element oxygen is

1. oxygen is needed for the rusting of iron
2. oxygen supports the burning of paper
3. oxygen has a density of 1.43 grams per liter
4. oxygen must be present for food to decay

The correct answer is option 3. Oxygen having a density of 1.43 grams per liter describes a physical property of the element oxygen. A physical property is a property that can be observed or measured without changing the composition of matter and density is one physical property.

The answer is 3. Oxygen having a density of 1.43 grams per liter describes a physical property of the element oxygen. A physical property is a property that can be observed or measured without changing the composition of matter and density is one physical property.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer