Bio- Ch 2

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.

element

The innermost electron shell of an atom can hold up to _____ electrons.

2

Which of these relationships is true of an uncharged atom?

The number of protons is equal to the number of electrons.

What determines the types of chemical reactions that an atom participates in?

the number of electrons in the outermost electron shell

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

6

Which of these refers to atoms with the same atomic number but different atomic masses?

These atoms are isotopes.

Fluorine’s atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?

10

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?

5

Which of the following subatomic particles always has a positive charge?

proton

Changing the number of _____ would change an atom into an atom of a different element.

protons in an atom

The atoms of different phosphorus isotopes _____.

have different numbers of neutrons

A(n) _____ refers to two or more atoms held together by covalent bonds.

molecule

A(n) _____ bond joins these two oxygen atoms.

double covalent

Atoms with the same number of protons but with different electrical charges _____.

are different ions

In salt, what is the nature of the bond between sodium and chlorine?

ionic

An ionic bond involves _____.

an attraction between ions of opposite charge

The type of bonding and the numbers of covalent bonds an atom can form with other atoms is determined by _____.

the number of unpaired electrons in the valence shell

A carbon atom and a hydrogen atom form what type of bond in a molecule?

nonpolar covalent bond

An ionic bond is formed when _____.

one atom transfers an electron to another atom

Hydrogen bonding is most often seen _____.

when hydrogen is covalently bonded to an electronegative atom