Chapter 2

Question 0

Living organisms and everything around them are composed of what?

Answer 0

Matter

Question 1

A substance that cannot be broken down to other substances by chemical means

Answer 1

Element

Question 2

What is matter?

Answer 2

Anything that occupies space and has mass

Question 3

What are the three forms of mass?

Answer 3

• Solid
• Liquid
• Gas

Question 4

How many elements do we know of today?

Answer 4

92

Question 5

What is a compound?

Answer 5

A substance consisting of two or more different elements combined in a fixed ratio.

Question 6

What for element make up about 96% of the weight of our bodies?

Answer 6

Oxygen
Carbon
Hydrogen
Nitrogen

Question 7

What is a trace element?

Answer 7

An element that is essential for life but required in extremely minute amounts.

Question 8

What is an atom?

Answer 8

The smallest unit of matter that retains the properties of an element.

Question 9

Where does the name “atom” come from?

Answer 9

The Greek word meaning “indivisible”

Question 10

What are the three subatomic particles we will be learning about?

Answer 10

• Proton
• Electron
• Nucleus

Question 11

What is a proton?

Answer 11

A subatomic particle with a single positive electrical charge, found in the nucleus of an atom.

Question 12

What is an electron?

Answer 12

A subatomic particle with a single negative electrical charge. One or more electrons move around the nucleus of an atom.

Question 13

What is a neutron?

Answer 13

A subatomic particle having no electrical charge, found in the nucleus of an atom.

Question 14

What is an atomic number?

Answer 14

The number of protons in each atom of a particular element.

Question 15

Unless otherwise indicated an atom has an equal number of what?

Answer 15

Protons and electrons.

Question 16

What is a mass number?

Answer 16

The sum of the number of protons and neutrons in an atom’s nucleus.

Question 17

The mass of a proton and the mass of a neutron are measured in what unit of measurement?

Answer 17

The Dalton

Question 18

What is atomic mass?

Answer 18

The total mass of an atom; also called atomic weight. Given as a whole number, the atomic mass approximately equals the mass number.

Question 19

What is an isotope?

Answer 19

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons.

Question 20

What is a radioactive isotope?

Answer 20

An isotope whose nucleus decays spontaneously, giving off particles and energy.

Question 21

What do biologists use as tracers?

Answer 21

Radioactive isotopes.

Question 22

Mass amounts of what we’re released in Chernobyl.

Answer 22

Radioactive isotopes

Question 23

What varies in electrons.

Answer 23

The amount of energy they possess

Question 24

What are the energy levels that electrons move a around called?

Answer 24

Electron shells

Question 25

What does the amount of electron shells depend on?

Answer 25

The element's atomic number

Question 26

What is discrete volumes of space where electrons are commonly found?

Answer 26

Orbitals

Question 27

How many electrons can an orbital hold?

Answer 27

A maximum of two

Question 28

What is the outermost electron shell called?

Answer 28

Valence Shell

Question 29

What determines the chemical properties of an atom?

Answer 29

The amount of electrons in the valence shell

Question 30

How do chemical interactions between atoms enable them to fill their outer electron shell?

Answer 30

Each atom will share, donate, or receive electrons.

Question 31

How many covalent bonds can an atom form?

Answer 31

It depends on the amount of electrons needed to complete the outer shell

Question 32

How many chemical elements are essential to life?

Answer 32

25

Question 33

How many elements make up 96% of living matter?

Answer 33

Four

Question 34

What elements make up 96% of living matter?

Answer 34

Carbon Oxygen Hydrogen Nitrogen

Question 35

What trace element is required by all organisms?

Answer 35

Iron (Fe)

Question 36

What is required by an organism but only in minute amounts?

Answer 36

Trace elements

Question 37

What is required for normal activity of the human thyroid gland?

Answer 37

0.15 mL of iodine

Question 38

A type of weak chemical bond formed when the partially positive hydrogen atom participating in a polar covalent bond in one molecule is attracted to the partially negative atom participating in a polar covalent bond in another molecule (or in another region of the same molecule).

Answer 38

Hydrogen bond

Question 39

A chemical bond resulting from the attraction between oppositely charged ions.

Answer 39

Ionic bond

Question 40

A molecule containing polar covalent bonds and having an unequal distribution of charges.

Answer 40

Polar molecule

Question 41

The making and breaking of chemical bonds, leading to changes in the composition of matter.

Answer 41

Chemical reaction

Question 42

A starting material in a chemical reaction.

Answer 42

Reactant

Question 43

An ending material in a chemical reaction.

Answer 43

Product

Question 44

The sticking together of molecules of the same kind, often by hydrogen bonds.

Answer 44

Cohesion

Question 45

The attraction between different kinds of molecules.

Answer 45

Adhesion

Question 46

A liquid that is a homogeneous mixture of two or more substances.

Answer 46

Solution

Question 47

The dissolving agent of a solution. Water is the most versatile solvent known.

Answer 47

Solvent

Question 48

A substance that is dissolved in a solution.

Answer 48

Solute

Question 49

A solution in which water is the solvent

Answer 49

Aqueous solution

Question 50

A substance that increases the hydrogen ion (H) concentration in a solution.

Answer 50

Acid

Question 51

A substance that decreases the hydrogen ion (H) concentration in a solution.

Answer 51

Base

Question 52

A measure of the relative acidity of a solution, ranging in value from 0 (most acidic) to 14 (most basic). The letters pH stand for potential hydrogen and refer to the concentration of hydrogen ions (H).

Answer 52

pH scale

Question 53

A chemical substance that resists changes in pH by accepting hydrogen ions from or donating hydrogen ions to solutions.

Answer 53

Buffer

Question 54

Formed by sharing a pair of valence electrons by two atoms

Answer 54

Covalent bond

Question 55

Chemicals are the things that make up what?

Answer 55

Our bodies The bodies of organisms The physical environment

Question 56

Life first evolved in where?

Answer 56

Water

Question 57

Imagine that you have been hired as a chemist and your first task is to examine a newly discovered atom. The paperwork you're given states that it's atomic number is 110. What does this mean?

Answer 57

The atom contains 110 protons

Question 58

Radioactive isotopes are biological tools that are often used for what?

Answer 58

To detect brain tumors

Question 59

For an atom to achieve maximum stability and become chemically inert, what must occur?

Answer 59

It's outermost energy shell must be filled with electrons

Question 60

The formation of ions involves what

Answer 60

Gain or loss of electrons

Question 61

If a certain atom has a tendency to lose two electrons, this lends itself to the formation of a(n)?

Answer 61

Ion

Question 62

Radioactive isotopes are biological tools that are often used to

Answer 62

Detect brain tumors

Question 63

The formation of ions involves what?

Answer 63

Gain or loss of electrons

Question 64

If a certain atom has a tendency to lose two electrons, this lends itself to the formation of an

Answer 64

Ion