chem final 10th grade

1a

alkilai metals

2a

alkaline earth metals

7a

halogens

8a

noble gases

Democritus

Proposed matter is made of tiny particles called atoms

John Dalton

Modern Atomic Theory

J.J. Thomson

Discovered the electron using the cathode ray tube; Plum Pudding Model

Robert Millikan

Measured electron charge (Oil Drop Experiment)

Ernest Rutherford

Gold Foil Experiment; discovered nucleus

James Chadwick

Discovered neutron

Henry Moseley

Discovered atomic number

Proton

+1

Neuclus

1 amu

neutron

0

Neuclus

1 amu

electron

-1

electron cloud

0 amu

atom

Smallest piece of an element that keeps its properties.

Ion

An atom with a charge because it gained or lost electrons.

isotope

Atoms of the same element with different numbers of neutrons.

Four Characteristics of Waves

1. Wavelength (λ)

2. Frequency (ν)

3. Amplitude

4. Speed

Order from longest wavelength to shortest:

Radio → Microwave → Infrared → Visible → Ultraviolet → X-Ray → Gamma

Photoelectric Effect

Light can act like particles (photons).

s

Sphere

2

p

dumbell

6

d

complex

10

f

complex

14

Aufbau Principle

Fill lowest energy levels first.

Mendeleev

Created first periodic table.

mosley

arranged by atomic number

periodic law

Properties repeat when elements are arranged by atomic number.

metals

• Shiny

• Conduct electricity

• Malleable

Atomic Radius

⬇ Down Group = Increases

➡ Across Period = Decreases

Ionization Energy

⬇ Down Group = Decreases

➡ Across Period = Increases

electronegativity

⬇ Down Group = Decreases

➡ Across Period = Increases

Electron Affinity

Generally increases across a period.

octet rule

Atoms gain, lose, or share electrons to get 8 valence electrons.

cation

positive

antion

negative

Properties of Ionic Compounds

• High melting points

• Crystal structure

• Conduct electricity when dissolved

• Brittle

Covalent Bond

Sharing electrons between nonmetals.

Molecule