GHSGT SCIENCE REVIEW

What’s the test over?

• 25% - Cells and Heredity• 17% - Ecology• 26% - Structure and Properties of

Matter• 16% - Energy Transformations• 16% - Forces, Waves, and Electricity

ATOMIC STRUCTURE &

PERIODIC TABLE

What are subatomic particles?

• Protons• Neutrons• Electrons

Subatomic particle

Location Mass charge

PROTON In the nucleus

1 amu Positive+

NEUTRON In the nucleus

1 amu Neutral0

ELECTRON Orbits the nucleus (electron cloud)

1/1836 amu

Negative-

Where are electrons found?

• Electrons are in the electron cloud• Electron cloud is divided into energy levels• Energy levels closest to the nucleus hold

electrons with less energy while those farther from the nucleus have more energy

ENERGY LEVEL

NUMBER OF ELECTRONS

1ST 2

2ND 8

3RD 18

4TH 32

ATOMS:

BOHR MODELS OF ATOMS

What are valence electrons?

• Electrons in the outermost energy level• Valence electrons determine how an element

will react chemically with another element

How can the number of valence electrons an atom has be determined?• Look at the column the element is in on the

periodic table.• Column 1 = 1 valence electron• Column 2 = 2 valence electrons• Column 13 = 3 valence electrons (can never

have more that 8 valence electrons)• Column 17 = 7 valence electrons

PERIODIC TABLE

What is the atomic number of an element?

• Atomic number is the number of protons in an atom of a particular element

• How do you find the atomic number on the periodic table?– It is the whole number

How many protons?

Carbon_____ Neon _____

Sodium_____ Lithium_____

How can you find the number of electrons in an atom?

• The number of electrons will be the same as the number of protons (atomic number) (whole number) as long as the atom does not have a charge.

• How many electrons?Carbon_____ Neon _____

Sodium_____ Lithium_____

What is an isotope?

• Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons• EX: C-12 and C-14 are isotopes

Examples of isotopes

C-12: protons 6 neutrons +_6__atomic mass 12

C-14: protons 6 neutrons +_8__atomic mass 14

What is the atomic mass?

• The average mass of all the isotopes of an element.

• How can you look at the periodic table and tell the atomic mass?– It is the number with digits behind the decimal (NOT

the whole number)– EX: Atomic mass for: Carbon _________

Lithium_________ Neon__________ Sodium_________

How can you tell the number of neutrons an atom has?

• The atomic mass rounded off is the number of protons plus the number of neutrons.

• To get the number of neutrons: round of the atomic mass and subtract the atomic number from it (remember: round of the bigger number and subtract the smaller number to get neutrons)

• EX: Na 23 – 11 = 12 (number of neutrons)• Atomic mass – Atomic number = Neutrons

What is the number of neutrons in the following?

Carbon _________ Neon________

Lithium_________ Sodium________

What is a family on the periodic table?

• A vertical column• Each family consists of element with similar

properties• AKA: Groups

Alkali Metals

Alkaline Earth Metals

Transition Metals

Boron Family

Carbon Family

Nitrogen Family

Oxygen Family

Halogens

Nobel Gases

Lanthanides & Actinides

What is a period on the periodic table?

• A horizontal row• There are 7 periods on the periodic table

What is special about a period?

• All the elements within a period have the same number of energy levels (when you draw the Bohr models, the energy levels are the circles)

• EX: Period 1 = 1 energy level Period 3 = 3 energy levels

Period 5 = 5 energy levels

Where are the metals located on the periodic table?

• Metals are on the left side of the staircase (zig-zag line)

Properties of Metals:

• Most are solids at room temperature• Have luster (shiny)• Good conductors of heat and electricity• Malleable (can be hammered into sheets)• Ductile (can be made into wires)

Where are the nonmetals located on the periodic table?

• Nonmetals are on the right side of the staircase (zig-zag line)

Properties of Nonmetals:

• Most are gases or solids at room temperture• Brittle (break easily)• Dull in appearance• NOT good conductors of heat and electricity

Where are the metalloids located on the periodic table?

• Metalloids touch a side of the staircase (zig-zag line)

• The followingtouch the linebut are NOT metalloids:

AluminumPolonium

Properties of Metalloids:

• Metalloids have some properties of both metals and nonmetals