Chemical reactions happen when . a. atoms attract or repel one another b. heat is created by friction c. two or more substances are mixed substances are heated or d. cooled

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