What is the molarity of a solution that contains 4.13g of magnesium bromide in 0.845 l of solution

RMM magnesium bromide=184
184g=1 mol
4.13g will have=4.13*1/184=0.022mols
molarity=0.022/0.845=0.027M

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