Chemistry Chp 13 (T2)

Quarks

particles protons and neutrons are made up of

Two types of quarks

up quarks and down quarks

Each of these quarks has about

one-third of the mass of a proton or neutron and is electrically charged

Up quark

+2/3

Down quark

-1/3

_quarks are needed to make a proton or neutron

3

Protons

2 up quarks and 1 down quarks

Neutron

1 up quark and 2 down quarks

Quarks are held together by the

color force, a form of the strong nuclear force

Color force is a force that is much

stronger than the force binding protons and neutrons to each other

an atom normally has the _ _ _ _ number of protons and electrons and thus has no overall electric charge

same

A variety of influences, such as

heat, electrictiy, radiation and chemical interactions can cause an atom to gain or lose elctrons in its outermost (valence) shell

Ion

an atom that has an electric charge because of losing or gaining electrons

If an atom gains electrons, it will have

more electrons than protons and will posses a net negative charge

If an atom loses electrons, it will have

more protons than elctrons and will posses a net positive charge

Anion

Negative ion

Cation

Positive ion

Mass number (theoretical)

Approximate measure of the atom’s mass

Is the total number of protons + neutrons in the nucleus

(usually in superscript)

These numbers are always

whole numbers because they represent numbers of whole particles

The mass of number of typical aluminum atom is 27

Protons: (), Neutrons (), electrons (_)

13,14,13

Explain Protons: (13), Neutrons (14), electrons (13)

Atomic number is the number of protons

Mass number substracted by the number of protons is number of neutron

Number of electrons are equal to the number of protons

Atoms with higher mass number have

more actual mass than atoms with lower mass number

Atomic numbers

Numbers of protons ONLY

Actual weight

(usually in subscript)

Solid sphere model

John Dalton

Drew upon Anicent Greek’s idea of atoms

Stated that atoms are indivisble

Given elements are identical

Compound are combination of different types of atom

Plum pudding model

J.J Thomson

Discovered electrons in 1897 = won Noblel Prize

Model shows atoms as composed of electrons scattered throughout a spherical cloud of positive charges

Nuclear model

Ernest Rutherford

Fired positively charged alpha particels at a thin sheet

Most passed through with little deflection, but some deflected at large angles =

only possible if the positive charges are concentrated at the center (nucleus)

Planetary model

Niels Bohr

Modified Rutherford’s model = electrons moved around the nucleus in orbits fo fixed sizes and enrgy

Electron enrgy quantised

Quantum model

Erwin Schrödinger

State that electrons move in waves = impossible to know the exact location of the electrons

Clouds of probability = where we are more likely to find an electron

Electrons do

NOT absorb or release energy in a smooth flow

Rather, energy is always absorbed or released in a discrete “packet“ called ________

quantum

Energy can

NOT be in between stages, it must be in a specific energy level

Electrons changes shells when they

gain or lose energy

When electrons gain a quantum of energy

it moves farther away from the nucleus

When electrons looses a quantum of energy

it moves closer to the nucleus

Quantum theory by

Max Plank

Uncertaintity principle by

Wrener Heisenberg

Uncertaintity principle

It is impossible to measure both the position and velocity of an electron with certainty

Electron Clouds by

Max born & accredited to Erwin Schrödinger

Electron Cloud model

Electrons do NOT have definte orbits around the nucleus, instead electrons move unpredicatbly inside regions called orbitals

Each orbital can hold up to

two electrons

Each electrons shell is made up of

one or more orbitals

Each orbitals in the elctron cloud model can be visualized as

cloud in which dots indicate the probality of findig an electron, the greater the density of dots, the greater the porbabiltiy of finding an electron