Elements in an element group have similar 1) atomic number.
2) mass number.
3) chemical symbols.
4) chemical properties and the same number of valence electrons.

Adrop of acetone (nail polish remover) has a mass of 35 mg and a density of 0.788 g/cm3. what is its volume in cubic centimeters?

An atom's configuration based on its number of electrons ends at 3p4. another atom has seven more electrons. starting at 3p, what is the remaining configuration? 3p63d34s2 3p43d54s2 3p64s23d3 3p44s23d

How is the way a mixture is combined different from how a compound is combined?