An unknown substance is measured. It has a mass of 0.221 g and a volume of 2.25 mL. What is its density?

d ≈ 0.098 g/mL

Explanation:

The density of a substance can be found by dividing the mass by the volume.

d=m/v

The mass of the substance is 0.221 grams and the volume is 2.25 milliliters.

m= 0.221 g

v= 2.25 mL

Substitute the values into the formula.

d= 0.221 g / 2.25 mL

Divide

d= 0.098222222 g/mL

Let’s round to the nearest thousandth. The 2 in the ten thousandths tells us to keep the 8 in the thousandth place.

d ≈ 0.098 g/mL

The density of the substance is about 0.098 grams per milliliter.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.