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 Location
particle
Mass
charge
PROTON
In the
nucleus
1 amu
Positive
+
NEUTRON
In the
nucleus
1 amu
Neutral
0
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
neutrons
atomic mass
6
+_6__
12
C-14: protons
neutrons
atomic mass
6
+_8__
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 following
touch the line
but are NOT
metalloids:
Aluminum
Polonium
Properties of Metalloids:
• Metalloids have some properties of both
metals and nonmetals