Unit 1: Periodic Table, Atoms & Elements

Question 1

Atomic theory

Answer 1

the theory that all matter can be broken down to individual “fundamental pieces” which cannot be divided further

Question 2

Matter can be divided into two types of pure substances

Answer 2

elements and compounds

Question 3

Element

Answer 3

Matter that cannot be broken down into smaller substances (made from one type of atom)

Question 4

The smallest unit of a compounds is a

Answer 4

molecule

Question 5

Molecule

Answer 5

One or more types of atoms bonded together

Question 6

4 fundamental assumptions laid out by John Dalton

Answer 6

1. All matter is composed of atoms
2. The atoms of a given element differ from the atoms of all other elements.
3. Compounds are combinations of atoms; each molecule of the same compound has the same number and types of atoms.
4. Atoms are not created or destroyed by chemical reactions.

Question 7

All matter is composed of

Answer 7

Atoms

Question 8

The atoms of a given element ___ from the atoms of all other elements.

Answer 8

differ

Question 9

Compounds are

Answer 9

combinations of atoms; each molecule of the same compound has the same number and types of atoms

Question 10

Atoms are not ___ by chemical reactions.

Answer 10

created or destroyed

Question 11

Law of Constant Composition

Answer 11

The composition of pure substances always stays the same

Question 12

Law of Conservation of Mass

Answer 12

Atoms are not created or destroyed by chemical reactions.

Question 13

Both compounds and elements are considered __ substances

Answer 13

pure

Question 14

How many known elements exist?

Answer 14

110

Question 15

Every type of matter or substance on earth comes from

Answer 15

A distinct element or compound

Question 16

Every element has been assigned a

Answer 16

Name and symbol

Question 17

Atomic symbol

Answer 17

abbreviations for elements on the periodic table

Question 18

Compounds contain whole number ratios of

Answer 18

atoms

Question 19

We represent compounds (multiple elements) by

Answer 19

listing the symbol, followed by the quantity (amount present) of each element

Question 20

When writing out compounds, parentheses are used to indicate

Answer 20

more than one group of atoms

Question 21

Atoms are the smallest unit of matter, but they are actually composed of

Answer 21

smaller units with a different charge & mass

Question 22

Protons

Answer 22

positively charged particles located in an atoms nucleus, along with neutrons

Question 23

Neutrons

Answer 23

particles with no charge (neutral) that reside in the nucleus with protons.

Question 24

Electrons

Answer 24

negative charged particles that orbit an atoms nucleus. There are the same number of electrons as there are protons. Have no significant mass (weight).

Question 25

The identity of an element is defined by the number of

Answer 25

protons in the nucleus

Question 26

Atomic number (Z)

Answer 26

The identity of an element, which is determined by the number of protons in an atoms nucleus

Question 27

If an atom somehow lost a proton (it’s identity) it would cease to be

Answer 27

the same element.

Question 28

If the number of electrons is equal to the number of protons, then the charge is

Answer 28

0 or neutral

Question 29

If there are more electrons than protons, then the charge is

Answer 29

negative

Question 30

If there are more protons than electrons, the charge is

Answer 30

positive

Question 31

protons - electrons =

Answer 31

charge

Question 32

The strength of the charge depends on

Answer 32

how many more electrons there are of protons, or vice versa

Question 33

Ion

Answer 33

atom with a charge (unequal proton/electron). An ion is always part of an isotope.

Question 34

An atom with a charge (ion) means that the protons and electrons are

Answer 34

not equal (neutral)

Question 35

Cation

Answer 35

An ion with a positive charge

Question 36

Anion

Answer 36

An ion with a negative charge

Question 37

We express ions in shorthand notation by

Answer 37

putting the charge in superscript immediately following the atom. ie. P^3- or AI^3+

Question 38

A change in the number of neutrons an atom has does not

Answer 38

Change the identity or charge.

Question 39

Protons + Neutrons =

Answer 39

Mass

Question 40

Atomic mass - Atomic number (protons) =

Answer 40

electrons

Question 41

Isotopes

Answer 41

Two atoms of the same element with a different number of neutrons (different MASS) All atoms are isotopes, regardless of whether or not they are ions

Question 42

How do we specify the mass of isotopes in superscript?

Answer 42

in the top left-hand corner of the symbol. ie potassium-39 is ^39K

Question 43

In a neutral element, there is ___of protons, electrons and neutrons

Answer 43

the same number

Question 44

The amount of protons never changes, so if we have an isotope (scripted # to the left of element), we

Answer 44

subtract the atomic number (protons) with the isotope mass listed and this will tell us the amount of neutrons. (remember isotope means it is charged and not in a neutral state and will be written in the top left corner of the element name). If it has a charge written to the top right we with add or subtract that from the atomic number to get the amount of electrons present.

Question 45

the total mass given on the periodic table is a __ average of the masses of each element’s isotopes

Answer 45

weighted

Question 46

How do we find a weighted average?

Answer 46

(isotope * % of abundance) + (isotope * % of abundance)

Question 47

The term “period” (periodic table) refers to

Answer 47

horizontal rows of elements which repeat the last line or pattern of reactivity.

Question 48

The term “group” in the periodic table refers to

Answer 48

vertical columns of elements which are grouped together by properties.