Chapter 2 quiz

Question 1

What is matter

Answer 1

Anything that takes up space and has mass, matter is made of elements

Question 2

What is an element

Answer 2

A substance that cannot be broken down into other substances by chemical reactions

Question 3

How many elements are in nature and which ones are important

Answer 3

92 elements, CHON and important because they are 96% of living matter

Question 4

What is a compound

Answer 4

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

Question 5

What is emergent property

Answer 5

When compounds have characteristics different from the compound’s elements

Question 6

What are essential elements

Answer 6

Elements that an organism needs, makes up 20-25% of the 92 natural elements. Essential elements differ in organisms, humans need 25 and plants need 17.

Question 7

What are trace elements

Answer 7

elements needed in small quantities (like iron). Some trace elements are need in all organisms, some are needed in some organisms

Question 8

Describe evolution in the textbook (this question might not be important)

Answer 8

Some species adapt to environments with toxic elements

Question 9

What is an atom

Answer 9

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

Question 10

what are subatomic particles

Answer 10

what atoms are composed of, they are protons neutrons and electrons.

Question 11

what keeps electrons near the nucleus and what do electrons form around the nucleus

Answer 11

attraction between opposite charges keeps the electrons near the nucleus. Electrons form a cloud of negative charge around the nucleus

Question 12

What is the nucleus (atomic nucleus)

Answer 12

the nucleus is at the center of an atom, contains protons and neutrons. Protons give the nucleus a positive charge.

Question 13

What is the atomic number

Answer 13

the number of protons which is unique to the element
(atoms have the same number of protons and electrons)

Question 14

What is the mass number

Answer 14

the total number of protons and neutrons in the nucleus

Question 15

What is an isotope

Answer 15

atoms with the same number of protons but different number of neutrons (more neutrons)
Isotopes have greater atomic mass but behave the same in chemical reactions

Question 16

what is a radioactive isotope

Answer 16

an isotope where it’s nucleus decays, giving off particles and energy

Question 17

how are radioactive isotopes used

Answer 17

to track metabolic processes, measure radioactive decay in fossils to date them and prove evolution since you can see organisms from the past and present

Question 18

What is energy

Answer 18

the capacity to cause change, such as doing work

Question 19

what is potential energy

Answer 19

energy that matter possesses because of its location or structure

Question 20

how does matter move relative to potential energy

Answer 20

matter naturally moves to the lowest state of potential energy.

Question 21

Why do electrons have potential energy

Answer 21

electrons have potential energy due to their distance to the nucleus, the negatively charged electrons are attracted to the positively charged nucleus

Question 22

describe the first, second and third shell

Answer 22

the first shell is closest to the nucleus and can hold 2 electrons, lowest potential energy. The second shell can hold 8 electrons, higher energy. the third shell can hold 18 electrons, higher energy

Question 22

what is an electron shell

Answer 22

where electrons are found, each shell had an average distance and energy level

Question 23

how can electrons move from shell to shell

Answer 23

electrons can move from a shell to another by gaining or losing energy equal to the difference in potential energy in the old shell to the new shell

Question 24

What is a valence electron

Answer 24

valence electrons are electrons on the outermost shell, or the valence shell chemical behavior of an atom depends on valence electrons

Question 25

describe what happens when you change the number of protons, neutrons and electrons

Answer 25

changing the number of protons changes its identity or atomic number changing the number of neutrons changes its mass number changing the number of electrons changes the atom's charge, chemical reactivity/behavior

Question 26

what are chemical bonds

Answer 26

interactions between atoms that are closely held together

Question 27

what is a covalent bond

Answer 27

the sharing of a pair of valence electrons by 2 atoms

Question 28

what is a molecule

Answer 28

2 or more atoms held by covalent bonds

Question 29

what is electronegativity

Answer 29

the attraction of a particular atom for the electrons of a covalent bond more electronegativity=atom pulls electron more strongly

Question 30

what is a non-polar covalent bond

Answer 30

electrons are shared equally between atoms, atoms have same/similar electronegativity

Question 31

what is a polar covalent bond

Answer 31

electrons are shared unequally, one atom is more electronegative than the other

Question 32

what is partially negative and positive charged

Answer 32

In polar covalent bonds, the atom that is more electronegative is partially negative charged, the other atom is partially positive charged

Question 33

What is an ionic bond

Answer 33

the transfer of valence electrons between atoms. Happens when electronegativity difference is really high

Question 34

What are ions

Answer 34

the atoms that go through an ionic bond. Oppositely charged ions attract.

Question 35

what is a cation and an anion

Answer 35

a cation is the positively charged ion, it loses an electron an anion is the negatively charged ion, it gains an electron

Question 36

What are ionic compounds

Answer 36

compound formed by ionic bonds, they are salts.

Question 37

what is a hydrogen bond

Answer 37

the noncovalent bond between a hydrogen atom and an electronegative atom the electronegative atom is of another molecule or is in a bigger molecule the electronegative atom is partially negatively charged, hydrogen is partially positive

Question 38

molecule shape question

Answer 38

Molecule's shape and size determines its function and how biological molecules recognize and respond to one another

Question 39

what is a chemical reaction

Answer 39

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

Question 40

what is a reactant and product

Answer 40

reactant - chemicals before the reaction product - chemicals after the reaction

Question 41

how is the concentration of reactant molecules important

Answer 41

the greater the concentration of reactant molecules, the more frequently they collide with one another and have an opportunity to react and form products same is true for products for reverse reactions

Question 42

what is chemical equilibrium

Answer 42

when forward and reverse reactions occur at the same rate reactions are still happening, concentrations are at a particular ratio, doesn't have to be the same.