Chemistry & Water Test (Honors Bio)

Atoms are composed of

• protons with a positive charge
• neutrons with no charge
• electrons with a negative charge
• All of the above

The smallest particle of carbon that can retain the chemical properties of carbon is

• a carbon molecule.
• a carbon macromolecule.
• a carbon atom.
• the nucleus of a carbon atom.

A substance that is composed of only one type of atom is called a(n)

• nucleus.
• element.
• compound.
• molecule.

All matter in the universe is composed of

• cells.
• molecules.
• atoms.
• carbon.

The electrons of an atom

• have a positive charge.
• are found in the nucleus along with the protons.
• are attracted to the positive charge of neutrons.
• orbit the nucleus in various energy levels.

Because carbon has four valence electrons in its outer energy level,

• it can form bonds with carbon atoms only.
• these atoms are naturally chemically stable.
• it can react with up to four other atoms to form covalent bonds.
• it cannot react with anything because it is stable.

An atom that has gained or lost electrons is called a(n)

• isotope.
• ion.
• molecule.
• element.

What information does the atomic number of an element provide to a biology student?

• The total number of protons and neutrons in the nucleus.

• The number of electrons in the outermost energy level.

• The mass of the atom in atomic mass units (amu).

• The number of protons in the nucleus, determining the element's identity.

What subatomic particle always determines the atomic number of an atom?

• number of neutrons
• number of electrons
• the number of protons plus the number of neutrons
• number of protons

What is a key difference between nonpolar covalent bonds and polar covalent bonds?

• Nonpolar covalent bonds involve sharing electrons equally, while polar covalent bonds involve an unequal sharing of electrons.

• Nonpolar covalent bonds occur only between atoms of the same element, while polar covalent bonds involve different elements.

• Nonpolar covalent bonds result in the formation of ions, while polar covalent bonds do not.