AP BIOLOGY

Detailed explanation-1: -Strong linkages-called covalent bonds-hold together the hydrogen (white) and oxygen (red) atoms of individual H2O molecules. Covalent bonds occur when two atoms-in this case oxygen and hydrogen-share electrons with each other.

Detailed explanation-2: -A water molecule has three atoms: two hydrogen (H) atoms and one oxygen (O) atom. That’s why water is sometimes referred to as H2O. A single drop of water contains billions of water molecules.

Detailed explanation-3: -Water is a Polar Covalent Molecule Water (H2O), like hydrogen fluoride (HF), is a polar covalent molecule. When you look at a diagram of water (see Fig. 3-2), you can see that the two hydrogen atoms are not evenly distributed around the oxygen atom.

Detailed explanation-4: -Oxygen has 6 valence electrons while hydrogen has 1 valence electron. The oxygen requires two electrons to complete its octet, therefore it is two hydrogen atoms that form a polar covalent bond with one oxygen atom to make a water molecule.

Detailed explanation-5: -A: The oxygen atom shares one pair of valence electrons with each hydrogen atom. Each pair of shared electrons represents one covalent bond, so two covalent bonds hold the water molecule together.