Chapter 2 Elements and Chemical Bonds

How many valence electrons does sodium have?

• 1

• 2

• 8

• 11

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What does the nucleus of an atom contain?

• protons and electrons

• protons and neutrons

• electrons and neutrons

• protons, neutrons and electrons

What is represented by the dots in an electron dot diagram?

• the number of atoms sharing an electron

• the total number of electrons in an atom

• the number of valence electrons in an atom

• the number of electrons circling a nucleus

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Which element is the most chemically stable?

• beryllium

• nitrogen

• carbon

• neon

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What is the term for matter that is made up of two or more different kinds of atoms joined by chemical bonds?

• element

• compound

• metal

• noble gas

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Which feature distinguishes polar molecules from nonpolar molecules?

• Polar molecules contain atoms that are chemically bonded together.

• Polar molecules can contain more than one atom of the same element

• Polar molecules can contain atoms of different elements.

• Polar molecules contain electrons that are not shared equally by the atoms.

What is a covalent bond?

• A covalent bond is a bond in which two atoms share electrons.

• A covalent bond is a bond in which one atom gains an electron.

• A covalent bond is a bond in which two atoms contribute unequal numbers of electrons.

• A covalent bond is a bond in which all electrons remain with their original atoms.

Which of these is true of covalent compounds?

• They are usually solid at room temperature.

• They usually conduct electricity well.

• They usually have low boiling points.

• They usually have high melting points.

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How many bonds are shown in this structural formula of carbon dioxide?

• 1

• 2

• 3

• 4

Which of these two molecules show ionic bonding?

• H2O

• NaCl

• Both H2O and NaCl

• neither H20 and NaCl

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