Ch 2 Chemistry

Question 1

role: nucleus

Answer 1

neutrons and protons

Question 2

role: nuetrons

Answer 2

no charge, nucleus, determines isotope

Question 3

role: protons

Answer 3

positive charge, nucleus, determines element

Question 4

role: electrons

Answer 4

negative charge, participates in chemical reactions, outer-shell electrons determine chemical behavior, energy for cells

Question 5

Explain the octet rule and its importance to living things

Answer 5

driving force behind chemistry
- atoms want to have filled outer rings
- this means they want eight electrons, sometimes two electrons, in their outer ring
“an atom with a completed valence shell is unreactive; that is, it will not interact readily with other atoms”

Question 6

Describe how electronegativity affects how atoms bond

Answer 6

The electronegativity of an atom is how tightly and how “strongly” it pulls an electron towards itself. That tug-of-war is going to determine whether an electron is shared equally or not

Question 7

covalent bond

Answer 7

The sharing of a pair of valence electrons by two atoms. Electrons get passed back and forth between the two elements

Question 8

Compare and contrast polar and nonpolar covalent bonds.

Answer 8

both covalent bonds, which means they share a pair of valence electrons by two atoms, but in nonpolar covalent bonds the electrons are shared equally and in polar covalent bonds the electrons are not shared equally.

Question 9

What is an ionic bond?

Answer 9

One atom steals electrons from the other. The one losing an electron becomes positively charged, while the one gaining an electron becomes negatively charged. These atoms now attract each other.
“It may help you to think of the t in cation as a + sign, and of an anion as ‘A Negative ION.’” “Cations and anions attract each other; this aKrac4on is called an ionic bond.”

Question 10

What is a hydrogen bond

Answer 10

When a hydrogen atom is covalently bonded to an electronegative atom, the hydrogen atom has a partial positive charge that allows it to be attracted to a different electronegative atom with a partial negative charge nearby… noncovalent attraction between a hydrogen and an electronegative atom

• an attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or hydrogen

Question 11

compare/contrast ionic bonds and hydrogen bonds

Answer 11

ionic bonding exists between permanent anions and cations, whereas hydrogen bonds exist between partial positive and partial negative charges

Question 12

polar molecule

Answer 12

a region with a slight positive charge and a region with a slight negative charge