Four atoms of hydrogen combine with one carbon atom to form CH4, but only two hydrogen atoms combine with one oxygen atom to form H2O. Which of the following helps to explain why? More than one answer is correct A Oxygen has two vacancies in its electron shell, but carbon has four vacancies.
B Atoms may share electrons in order to fill their electron shells.
C Hydrogen has one valence electron.
D Metallic bonds form between positively charged metal ions and delocalized electrons.