What is similar about the bonding of hydrogen, chlorine, and fluorine atoms?

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

I’m really not sure what’s the answer. sorry

Ibelieve it's temperature! i'm not 100% sure.