McGraw-Hill Connect Homework on Atoms and Bonds

Ionic bond

-formed by an attraction between atoms with opposite chrages -bond that holds NaCl together -involves a transfer of one or more electrons from one atom to another -leads to the formation of a crystal lattice rather than distinct molecules -weakest type of bond shown (in this set)

Carbon (atomic number 6)

-has 4 valence electrons -most likely to share electrons -most likely to form covalent bonds

Single covalent bond

-type of bond that holds a molecule of hydrogen together -involves 2 atoms sharing 2 electrons

Chlorine (atomic number 17)

-has 7 valence electrons -most likely to gain an electron -highest electronegativity -closest to the right side of the Periodic Table -most likely to form an anion

Sodium (atomic number 11)

-most likely to lose an electron -lowest electronegativity -closest to the left side of the periodic Table -most likely to from a cation

None of these (other bonds in this set)

-the attraction between 2 different water molecules -involves 2 atoms sharing 1 electron -involves 2 atoms sharing 3 electrons

Double covalent bond

-type of bond that holds a molecule of oxygen together -involves 2 atoms sharing 4 electrons -strongest type of bond shown (in this set)

Indicate whether each of the following statements about the reactivity of elements is true or false. 1. The eight-element periodicity found in the Periodic Table is related to the number of electrons in the outermost energy level of the atoms that make up each element. 2. Electrons in the first energy level of an atom are called valence electrons. 3. For atoms important to life, if the first energy level is the outermost shell, it is stable with 2 electrons. If any other energy level is the outermost shell, it is stable with 8 electrons. 4. Atoms tend to react in ways that give each atom a stable outer shell of electrons. 5. Atoms with an outer shell that is almost empty are located on the right side of the Periodic Table while atoms with an outer shell that is full or almost full are located on the left side of the Periodic Table. 6. Atoms in the same row of the Periodic Table tend to have the same number of valence electrons. 7. Atoms with 7 valence electrons tend to be non-reactive.

1. TRUE 2. FALSE 3. TRUE 4. TRUE 5. FALSE 6. FALSE 7. FALSE

Indicate whether each of the following statements about covalent bonds is true or false. 1. A water molecule is 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. 3. Atoms differ in their affinity for neutrons, a property called electronegativity. 4. In general, electronegativity increases from left to right across each row of the periodic table and also increases down each column. 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. 6. A single molecule of oxygen (O2) is held together by two double nonpolar covalent bonds. 7. 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. 9. Although C and H differ slightly in electronegativity, this small difference is negligible, and C-H bonds are considered polar. 10. Of the 4 most common elements found in living organisms, nitrogen has the highest electronegativity and, therefore, the greatest 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.

1. TRUE 2. TRUE 3. FALSE 4. FALSE 5. TRUE 6. FALSE 7. TRUE 8. TRUE 9. FALSE 10. FALSE 11. TRUE