What is the mass, in grams, of a sample of 7.83 × 1024 atoms of helium (he)?

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Use this information to determine the number of calends electrons in the atoms. which of the following correctly compares the stability of the two atoms? a) both are unreactive b) both are highly reactive c) a is unreactive and d is reactive d) a is reactive and d is unreactive

The valence of aluminum is +3, and the valence of the chlorine is -1. the formula fir the aluminum chloride is correctly written as