Elements become denser toward the bottom of the periodic table. From left to right on the table, elements become denser toward the center of the table and less dense on either end.
In Column 1, hydrogen exists as a gas at 0 degrees Celsius and 1 atmosphere of pressure, while the other elements are liquids or solids. In Column 8 all the elements are gases under these conditions. The fact that an element exists as a solid does not indicate that it is denser than a liquid element. Mercury has a density of 13.53 grams per cubic centimeter and is a liquid while aluminum has a density of 2.70 grams per cubic centimeter and is a solid.