Radt 142 Exam 2

Atom

tiny basic building block of all matter

Most common way to picture an atom

solar system model (Bohr’s Model)

What are atoms made of?

protons, electrons, neutrons

Protons

positive electrical charge

Neutrons

no electrical charge

Electrons

negative electric charge

Nucleus

protons, neutrons

What determines the mass of an atom and why

mass of nucleus

protons and neutrons are larger than electrons

Element

any material or substance that is composed of only one type of atom

Compound

different elements combined during chemical change

Molecule

smallest particle of a compound

Mixture

two or more substances that are mixed but not chemically joined

air

Difference between compound and molecule

Molecule: formed when 2 or more atoms join chemically (O2)

Compound: molecule that contains at least 2 different elements (CO2)

All __________ are ____________ but not all _________ are ______________.

All compounds are molecules but not all molecules are compounds

__________ can’t be broken down

element

______ possess the same characteristics of the element

Atoms

________ have the same characteristics and is the smallest particle of a compound

Molecules

Maximum number in each shell

2n²

Maximum amount of electrons N shell can hold

32

2(4²)

2(16)

32

Outermost shell (_______ ______) of an atom is referred as a _________ ______.

electron orbit

valence shell

Electron Binding Energy

energy level where electron orbits around nucleus of atom

orbital levels closer to nucleus have greater biding energy than orbital levels further from nucleus

Which shell has the lowest binding energy

M

Which shell has the highest binding energy

K

What determines what the element will be

number of protons in nucleus

Atomic Mass

total number of protons and neutrons (nucleons/nucleus)

Atomic Number (z)

number of protons in nucleus determines what the element will be

Atomic mass formula

A = Z + N

atomic mass = atomic# + neutrons

X

atom’s elemental symbol

A

mass number

Z

atomic number symbol

What is 12

mass number

What is C

Atom’s elemental symbol

What is 6

atomic number symbol

Neutral Atom

stable

balanced protons and electrons

Ionized Atom

unbalanced protons and electrons

Ion

atom that gains or loses one or more electrons

Positive Charge Ion

electron is lost

Negative Charge Ion

electron is gained

2 Chemical bonds

Ionic

Covalent

Ionic

transfer of electron (gain or loss) between atoms

Covalent

sharing of electrons between atoms

Isotope

same number of protons

has different numbers of neutrons

Isotone

same number of neutron

diff number of protons

Isobar

same number of mass

diff atomic number (Z)

Nuclear Structure: Isotope

same z, diff A and N

Nuclear Structure: Isobar

same A, diff Z and N

Nuclear Structure: Isotone

same N, diff Z and A

Radioactivity

release of energy and matter

How does radioactivity occur

changes in nucleus of an atom

radioactive disintegration/decay

Half Life

period of time required for a quantity of radioactivity to be reduced ½ its original value

20 21

Radioactive decay results in the emission of what 3 things.

1. alpha particles

2. beta particles

3. gamma rays

Alpha particles

release of 2 neutrons and 2 protons

Beta particles

originate in nucleus

when emitted a neutron converts to proton

Gamma Rays

associated with alpha and beta emission

very high penetration power, health risk

1. Stopped by sheet of paper

2. Stopped by several feet of concrete or few inches of lead

3. Stopped by later of clothing or few millimeters of aluminum

alpha particles

gamma rays

beta particles

Smallest subdivision of a compounds that maintains the same characteristics of that compound

molecules

Smallest portion of element

atom

Two or more different atoms (elements)

compound and molecule

Two of more same atoms

molecules

What is a combination of different substances

mixture

7 electron shells

K = 2

L = 8

M = 18

N = 32

O = 50

P = 72

Q = 98