These are true and false questions and I want to make sure that I got them right.

1. A water molecule is held together by two single polar covalent bonds. False
2. Because oxygen has a greater electronegativity than hydrogen, water molecules are polar with two partial negative charges near the oxygen atom and one partial positive charge near each hydrogen atom. False
3. Atoms differ in their affinity for neutrons, a property called electronegativity. False
4. In general, electronegativity increases from left to right across each row of the periodic table and also increases down each column. False
5. In a nonpolar covalent bond there is an equal sharing of electrons between two atoms while polar covalent bonds involve an unequal sharing of electrons. True
6. A single molecule of oxygen (O2) is held together by two double nonpolar covalent bonds. True
7. A covalent bond is formed when two atoms share one or more pairs of electrons. True
8. Polar molecules are electrically neutral but the distribution of charge within the molecule is not uniform. True
9. Although C and H differ slightly in electronegativity, this small difference is negligible, and C–H bonds are considered polar. False
10. Of the 4 most common elements found in living organisms, nitrogen has the highest electronegativity and, therefore, the greatest affinity for electrons. False
11. A slightly positive hydrogen atom on one water molecule can attract the slightly negative oxygen atom on a different water molecule, leading to the formation of a hydrogen bond. False

Let's check your answers:

1. A water molecule is held together by two single polar covalent bonds.
False. A water molecule is actually held together by two single polar covalent bonds.

2. Because oxygen has a greater electronegativity than hydrogen, water molecules are polar, with two partial negative charges near the oxygen atom and one partial positive charge near each hydrogen atom.
True. This statement is true. Oxygen's higher electronegativity leads to an unequal sharing of electrons in a water molecule, resulting in a polar molecule.

3. Atoms differ in their affinity for neutrons, a property called electronegativity.
False. Electronegativity is a property of atoms that refers to their ability to attract electrons in a chemical bond, not their affinity for neutrons.

4. In general, electronegativity increases from left to right across each row of the periodic table and also increases down each column.
True. This statement is true. Electronegativity generally increases from left to right across a period and decreases from top to bottom within a group in the periodic table.

5. In a nonpolar covalent bond, there is an equal sharing of electrons between two atoms, while polar covalent bonds involve an unequal sharing of electrons.
True. This statement is true. Nonpolar covalent bonds involve equal sharing of electrons, while polar covalent bonds involve an unequal sharing of electrons.

6. A single molecule of oxygen (O2) is held together by two double nonpolar covalent bonds.
False. A single molecule of oxygen (O2) is held together by a double covalent bond, but it is considered polar because of the unequal sharing of electrons.

7. A covalent bond is formed when two atoms share one or more pairs of electrons.
True. This statement is true. A covalent bond is formed when two atoms share one or more pairs of electrons.

8. Polar molecules are electrically neutral, but the distribution of charge within the molecule is not uniform.
True. This statement is true. Polar molecules have an uneven distribution of charge, with one side being more positive and the other more negative, but overall they are electrically neutral.

9. Although C and H differ slightly in electronegativity, this small difference is negligible, and C–H bonds are considered polar.
False. C and H have a relatively small difference in electronegativity, resulting in nonpolar C-H bonds.

10. Of the 4 most common elements found in living organisms, nitrogen has the highest electronegativity and, therefore, the greatest affinity for electrons.
False. Oxygen has the highest electronegativity among the four most common elements found in living organisms.

11. A slightly positive hydrogen atom on one water molecule can attract the slightly negative oxygen atom on a different water molecule, leading to the formation of a hydrogen bond.
True. This statement is true. Hydrogen bonds are formed between a slightly positive hydrogen atom and a slightly negative atom of another molecule, such as water.

To answer these true or false questions, we'll need to understand some basic concepts related to chemical bonding and electronegativity.

1. A water molecule is held together by two single polar covalent bonds. - False
Explanation: False. A water molecule is made up of two hydrogen atoms bonded to one oxygen atom. The bonds between the hydrogen and oxygen atoms in water are considered polar covalent bonds, but there are only two bonds in a water molecule.

2. Because oxygen has a greater electronegativity than hydrogen, water molecules are polar with two partial negative charges near the oxygen atom and one partial positive charge near each hydrogen atom. - False
Explanation: False. Water molecules are polar, but they have a partial positive charge near the hydrogen atoms and a partial negative charge near the oxygen atom. This is because oxygen is more electronegative than hydrogen, and it attracts the shared electrons more strongly, resulting in the partial negative charge near oxygen.

3. Atoms differ in their affinity for neutrons, a property called electronegativity. - False
Explanation: False. Electronegativity is a property of atoms that refers to their affinity for electrons, not neutrons. Neutrons are electrically neutral particles found in the nucleus of an atom.

4. In general, electronegativity increases from left to right across each row of the periodic table and also increases down each column. - False
Explanation: False. Electronegativity generally increases from left to right across each row of the periodic table, but it decreases down each column. This means that atoms on the left side of the periodic table have lower electronegativity, while atoms on the right side have higher electronegativity.

5. In a nonpolar covalent bond, there is an equal sharing of electrons between two atoms, while polar covalent bonds involve an unequal sharing of electrons. - True
Explanation: True. In a nonpolar covalent bond, the electrons are shared equally between the two atoms. In a polar covalent bond, the electrons are shared unequally, with one atom having a stronger pull on the electrons, resulting in partial charges.

6. A single molecule of oxygen (O2) is held together by two double nonpolar covalent bonds. - True
Explanation: True. A molecule of oxygen (O2) is held together by two double covalent bonds, where each oxygen atom shares two pairs of electrons with the other oxygen atom. Since oxygen and oxygen have similar electronegativity, the bond is considered nonpolar.

7. A covalent bond is formed when two atoms share one or more pairs of electrons. - True
Explanation: True. A covalent bond is formed when two atoms share one or more pairs of electrons. This sharing of electrons allows both atoms to achieve a more stable electron configuration.

8. Polar molecules are electrically neutral, but the distribution of charge within the molecule is not uniform. - True
Explanation: True. Polar molecules have a difference in electronegativity between the atoms involved in the bond, leading to an uneven distribution of charge within the molecule. However, the overall charge of the molecule remains neutral.

9. Although carbon and hydrogen differ slightly in electronegativity, this small difference is negligible, and C–H bonds are considered polar. - False
Explanation: False. Although carbon and hydrogen have different electronegativities, the difference is considered negligible, and C-H bonds are generally considered nonpolar. The slight difference in electronegativity between these elements does not result in a significant uneven distribution of charge.

10. Of the four most common elements found in living organisms, nitrogen has the highest electronegativity and, therefore, the greatest affinity for electrons. - False
Explanation: False. The four most common elements in living organisms are carbon, hydrogen, nitrogen, and oxygen. Nitrogen does not have the highest electronegativity among these elements. Oxygen has the highest electronegativity, indicating its greater affinity for electrons.

11. A slightly positive hydrogen atom on one water molecule can attract the slightly negative oxygen atom on a different water molecule, leading to the formation of a hydrogen bond. - False
Explanation: False. A slightly positive hydrogen atom on one water molecule can attract the slightly negative oxygen atom within the same water molecule, leading to the formation of a hydrogen bond. Hydrogen bonds form between different water molecules or between different molecules, not within the same molecule.