Chapter 2: the chemical context of life

Question 1

Matter

Answer 1

Has mass
Occupies space

Question 2

Elements

Answer 2

Building blocks of matter
Can not be chemically broken down into other substances

Question 3

Compounds

Answer 3

Molecules containing atoms of 2 or more elements
Not all molecules are compounds but all compounds are molecules

Question 4

Deoxyribonucleic Acid (DNA)

Answer 4

Transmits information across generations
Holds information for building RNA proteins

Question 5

Sodium Metal, Chlorine Gas, Sodium Chloride

Answer 5

Highly reactive in water
Poison used in chemical warfare
Salt

Question 6

Elements of life

Answer 6

25 of 92 natural elements are essential for humans and must. have to live and reproduce
Bulk elements need in large amounts
Trace elements need in small amounts

Question 7

Atom

Answer 7

The smallest unit of matter that retains properties of that element

Question 8

Subatomic Particles

Answer 8

Proton: +, Nucleus
Neutrons: Neutral, nucleus
Electron: - , Electron cloud

Question 9

Protons and Nucleous

Answer 9

From nucleus
Central portion of atom
most of mass of atom
very small volume

Question 10

Electrons

Answer 10

small, constantly moving
electron cloud around nucleus
most of volume of atom

Question 11

Atomic Composition

Answer 11

Change # protons: Atom becomes new elements
Change # neutrons: Atoms becomes new isotope and remains same elements
Change # electrons: change charge and neutral becomes ion

Question 12

Describing elements

Answer 12

Atomic Number: # of protons
mass number: # protons + neutrons for one atom
Atomic Mass: the average mass of all isotope of an element

Question 13

Radioactivity

Answer 13

unstable isotopes decay, give off energy
carbon 14 to nitrogen 14

Question 14

Neutral atoms vs ions

Answer 14

Balanced charge
Same # protons as electrons
Changing # electrons
Makes charged - ion
Cation - positively charged
Anion - negatively charged

Question 15

Electrons

Answer 15

Most associated with chemical, bonding
orbitals hold electrons: max 2 electrons per orbital
orbitals into electron shells: 1st = 1 orbitals, 2nd = 4 orbitals, 3rd = 4 orbitals
outer - most occupied shell = valence shell

Question 16

Unpaired electrons

Answer 16

Atoms most stable when valence shell ( VS ) is full ( or becomes empty)

Question 17

Electronegativity

Answer 17

How strongly atoms attracts electrons

Question 18

Covalent bonds

Answer 18

Sharing electrons: Fills valence shell of both atoms and both increased stability
Single, double, triple bonds possible

Question 19

Ionic Bonds

Answer 19

Electrical attraction between action and anion
Large difference in electronegative
Atoms lose/gain electrons: forms ions
full valence shells for both

Question 20

Electronegativity and bonds

Answer 20

Sharing electrons = covalent bonds
equal= non polar covalent bond
unequal= polar covalent bond
Losing/gaining = ionic bond

Question 21

Polar Covalent bonds

Answer 21

Electron unequally shared
slight positive and slight negative

Question 22

Hydrogen bonds

Answer 22

Slight + and - attract
polar molecule to polar molecule

Question 23

Molecular shape

Answer 23

Determined by bonding
number of electrons pairs shared/atoms in molecule
central atom usually with space from 4 pair of valence electrons
Electrons repel each other
shared and unshared
negative repels negative

Question 24

structure/function relationship

Answer 24

forms determines function
form determine by: bonds within molecule, hydrogen bonds, aspects of environment

Question 25

Forming compounds

Answer 25

Chemical reactions
making/breaking bonds