Unit 3: atoms and the periodic chart

Question 1

proton

Answer 1

a positively charged particle in the nucleus

symbol: p⁺

Question 2

neutron

Answer 2

a neutral particle (has no charge) in the nucleus

symbol: n⁰

Question 3

electron

Answer 3

a negatively charged “particle” outside the nucleus

(actually more of a wave than a particle)

symbol: e^-

Question 4

ion

Answer 4

a charged atom or molecule

Examples: Na⁺, OH^-, Al⁺³

Question 5

cation

Answer 5

a positively charged atom or molecule

Examples: Na⁺, NH₄⁺

Question 6

anion

Answer 6

a negatively charged atom or molecule

Examples: Cl^-, SO₄^-2

Question 7

isotope

Answer 7

one type (weight) of an element

A difference in the number of neutrons

Examples: carbon-12 and carbon-14

Question 8

atomic mass

Answer 8

a weighted average of the naturally occurring isotopes of an element

the bigger number on the periodic chart, with decimals

protons + # neutrons = atomic mass

Question 9

How do you find the number of electrons?

Answer 9

find the atomic number and adjust for the charge

Example: F-

atomic number 9 + 1 extra electron = 10 e-

Question 10

atomic number

Answer 10

the number of protons

the smaller number on the periodic chart

a whole number

Question 11

How do you find the number of protons?

Answer 11

Look at the element’s atomic number.

Question 12

How do you find the number of neutrons?

Answer 12

Subtract the atomic number from the atomic mass.

Question 13

Rutherford’s experiment

Answer 13

Shot alpha particles (helium nuclei) at a thin piece of gold foil. Some particles went straight through, others were deflected. Demonstrated that atoms are mostly empty space with a dense core (nucleus). Disproved the plum pudding model.

Question 14

Bohr’s experiment

Answer 14

He electrified hydrogen gas until it glowed then separated the light with a prism. Demonstrated that there are particular wavelengths of light being given off, which is characteristic of the element. The atomic spectrum shows how much energy is released by the excited electrons falling back down to the ground state.

Question 15

Which atom has the larger atomic radius, Ca or Ca⁺²?

Answer 15

Ca

They have the same number of protons. Ca has two more electrons, which makes its electron cloud larger.

Question 16

Which atom has the larger atomic radius, F- or Na+?

Answer 16

F- They have the same number of electrons (10).

F has 9 protons and Na has 11. More protons pull in the electron cloud more, which makes Na+ the smaller atom.

Question 17

alpha decay

Answer 17

A radioactive atom breaks apart into two atoms, a helium nucleus (2 protons and 2 neutrons) and the left overs.

Question 18

beta decay

Answer 18

A radioactive atom breaks apart into an atom and an electron. One of the neutrons splits into a proton and an electron.

Question 19

4 sources of the elements

Answer 19

1-4 Big Bang

5-26 stellar fusion (the star’s life)

27-92 super nova (star death)

93+ man made

Question 20

alkali metals

Answer 20

first column

+1 charge

float

react with water

form bases

Question 21

alkali earth metals

Answer 21

second column

+2 charge

not as reactive as alkali metals

Question 22

transition metals

Answer 22

middle of the periodic chart

very stable (gold, silver, copper)

bright colors (sapphire, ruby, emerald, paint, etc)

can be +1, +2, or +3 charges

Question 23

metals

Answer 23

low electronegativity

good conductors of heat and electricity

malleable and ductile

form cations

Question 24

nonmetals

Answer 24

high electronegativity

gasses or brittle solids

poor conductors

form anions

Question 25

hallogens

Answer 25

7th column

-1 charge

very reactive

tend to form acids

diatomic (F₂, Cl₂, Br₂, I₂)

Question 26

Noble gases

Answer 26

8th column

no charge

completely stable; don’t react with anything

full s and p orbitals

Question 27

energy level

Answer 27

the row number

Question 28

valence electrons

Answer 28

the electrons in the outer energy level

same number as the column number

shown as dots around the symbol in a Lewis Dot Diagram

Question 29

electron configuration

Answer 29

A list of where the electrons reside in the electron cloud. Can be abbreviated using the nearest noble gas.

Question 30

quantum numbers

Answer 30

the 4 variables which define an orbital: n, l, m_l, m_s

The numbers are inserted into equations and graphed. The 3D graph shows the space where the electron is most likely to be found (the orbital).

Question 31

orbital

Answer 31

the region of space where an electron is likely to be found

Each orbital can hold two electrons (of opposite spin)

Question 32

s orbital

Answer 32

spherical

there is a single s orbital at every energy level

Question 33

p orbital

Answer 33

dumbell shaped

there are 3 p orbitals at every energy level except the first level

Question 34

d orbital

Answer 34

various shapes, including clover leaf

there are 5 d orbitals in the 3rd energy level and at all the higher energy levels

Question 35

f orbital

Answer 35

various shapes

4th energy level and above

there are 7 different f orbitals

Question 36

s block elements

Answer 36

Alkali metals and Alkali Earth metals

Question 37

p block elements

Answer 37

columns 3-8

includes all the nonmetals

Question 38

d block elements

Answer 38

the transition metals

because of the d orbitals, these elements have more than one stable charge

Ex: Fe⁺² and Fe⁺³

Question 39

f block elements

Answer 39

lanthanides and actinides (bottom two rows of periodic chart)