Science (Ch 2)

Question 1

Matter

Answer 1

anything that has mass and takes up space.

Question 2

Atom

Answer 2

the smallest particle of an element that still retains the properties of the element.

Question 3

Element

Answer 3

substance that is made of only one type of atom.

Question 4

Proton

Answer 4

particle inside the nucleus of an atom that has a charge of 1+.

Question 5

Neutron

Answer 5

particle without an electrical charge.

Question 6

Electron

Answer 6

particle with a negative charge.

Question 7

Atomic Number

Answer 7

number of protons in an atom’s nucleus.

Question 8

Mass number

Answer 8

the number of protons plus the number of neutrons in an atom.

Question 9

Isotope

Answer 9

atoms of the same element that have different numbers of neutrons.

Question 10

Compound

Answer 10

atoms of more than one type of element that are chemically bonded together.

Question 11

Molecule

Answer 11

a group of atoms connected by covalent bonds.

Question 12

Ion

Answer 12

electrically-charged atom whose charge results from an atom losing or gaining electrons.

Question 13

Mixture

Answer 13

a combination of substances in which the individual substances do not change or combine chemically but instead retain their own individual properties; can be gases, solids, liquids, or any combination of them.

Question 14

Heterogeneous mixture

Answer 14

a mixture which is not mixed evenly and each component retains its own properties.

Question 15

Homogeneous mixture

Answer 15

solid, liquid, or gas that contains two or more substances blended evenly throughout.

Question 16

Solution

Answer 16

a mixture which is evenly mixed throughout; also known as a homogeneous mixture.

Question 17

Density

Answer 17

measurement of the mass of an object divided by its volume.

Question 18

John Dalton theory of atoms:

Answer 18

1. Every element is made of tiny, unique particles called atoms that CANNOT be subdivided.
2. Atoms of the same element are exactly alike.
3. Atoms of different elements can join to form molecules.

Question 19

Niels Bohr suggested that electrons:

Answer 19

electrons move in set paths like planets that surround the sun.

Question 20

There are energy levels in which ___________ must move through. When an electron gains energy, it moves to a _________ _________ level. When it loses energy, it moves to a ________ __________ level.

Answer 20

There are energy levels in which electrons** must move through. When an electron gains energy, it moves to a **higher energy** level. When it loses energy, it moves to a **lower energy level.

Question 21

There are energy levels in which e_______ must move through. When an electron gains energy, it m_____ to a h______ e______ l_____. When it loses energy, it moves to a l_______ e_______ l______.

Answer 21

There are energy levels in which electrons must move through. When an electron gains energy, it moves to a higher energy level**. When it loses energy, it moves to a **lower energy level.

Question 22

There are energy levels in which _________ must move through. When an electron gains energy, it _____ to ______ ______ _____. When it loses energy, it moves to a _______ _______ ______.

Answer 22

There are energy levels in which electrons must move through. When an electron gains energy, it moves to a higher energy level**. When it loses energy, it moves to a **lower energy level.

Question 23

In the modern atomic model, electrons are found

Answer 23

in orbitals (s, p, d, f…) within each energy level.

Question 24

The electrons in the outermost energy level are called:

Answer 24

_ valence electrons._