Chapter 2: The Chemical Basis of Life

Question 1

What is ocean acidification?

Answer 1

a process by which greenhouse gases admitted to the atmosphere are getting into the ocean and changing the ocean’s composition

Question 2

What are all living organisms made of?

Answer 2

Cells!

Question 3

What are cells composed of?

Answer 3

Molecules

Question 4

What are molecules composed of?

Answer 4

atoms

Question 5

What are molecules?

Answer 5

made up of multiple atoms

Question 6

What are atoms?

Answer 6

the smallest basic structure of elements

Question 7

What is an element?

Answer 7

made of one type of atom, but can contain multiple of that atom

Question 8

What is the periodic table of elements?

Answer 8

depicts the different substances that exist in nature or that have been synthesized in labs or nuclear reactors’

Question 9

What elements are 96% of living matter composed of?

Answer 9

Hydrogen (H), Carbon ©, nitrogen (N), and oxygen (O)

Question 10

Where are protons, neutrons, and electrons located in an atom?

Answer 10

The nucleus contains protons and neutrons, with electrons ‘orbiting’ the outside

Question 11

protons

Answer 11

positive charge

Question 12

Neutrons

Answer 12

neutral charge

Question 13

Electrons

Answer 13

negative charge

Question 14

What is the atomic number?

Answer 14

the number of protons an atom has

Question 15

What is the mass number?

Answer 15

the number of protons + neutrons

Question 16

What is the atomic mass?

Answer 16

approximately equal to its mass number (takes electrons into account)

Question 17

What are isotopes?

Answer 17

the same number of protons but different numbers of neutronsForms of an element with different numbers of neutrons

Question 18

What does most an atom’s volume consist of?

Answer 18

empty space

Question 19

How are electrons organized?

Answer 19

located in different electron shells/orbitals, each with a characteristic distance from the nucleus

Question 20

How are chemical bonds formed?

Answer 20

An atom whose outer electron shell is not full tends to interact with other atoms and share, gain, or lose electrons, resulting in attractions

Question 21

How many electrons are needed for a full outer shell?

Answer 21

8

Question 22

How is an atom electrically neutral?

Answer 22

When the number of protons and the number of electrons in an atom are the same, the charges balance

Question 23

What is atomic weight?

Answer 23

an average of all the masses of the naturally occurring isotopes based on their abundance in nature

Question 24

How many electrons can each orbital hold?

Answer 24

2 (a pair)

Question 25

What is an atom’s valence shell?

Answer 25

The outermost electron shell of an atom

Question 26

What are valence electrons?

Answer 26

an electron in the outermost electron shell; these electrons tend to be involved in chemical bonding

Question 27

What is an atom’s valence?

Answer 27

The number of unpaired electrons found in an atom’s valence shell