What is the definition of a physical change?
No new substance is created and it can be reversed
What is the atomic number for Osmium?
76
In the equation: 2H2 + 20 -> 2H20 + H2 , which side is the products? (left or right)?
The right side
How many electrons can fit on the innermost shell (circle) in a Bohr model?
2 electrons
Draw a Bohr model for Fluorine
2nd: 7
What is the definition of a chemical change?
A new substance was created and it is impossible (or near impossible) to reverse.
What is the atomic mass for Potassium?
39
How many carbon are on the left side of the equation?
3C2H + C -> 3C2 + HC + H2
There are 7 carbon
3C2 = 6
C = 1
6 + 1 =7
How many electrons can fit on the 2nd shell (circle) of the Bohr model?
8 electrons
How many neutrons does Scandium have?
24 neutrons
Name TWO examples of a physical change.
Examples: cutting paper, sharping a pencil, food coloring, mixing sugar and salt, glass breaking
How many protons does Sodium have?
11 protons
How many hydrogen atoms are in the chemical equation below (both sides):
2H2O + HO -> H2O2 + H3
2H2O + HO -> H2O2 + H3
2H2 = 4 H2 = 2
H = 1 H3 = 3
4 + 1 = 5
2 + 3 = 5
5 + 5 =10 hydrogen
What element is shown here?
Aluminum
Name an example of a chemical change that we did during a lab in class
multiple answers
Name TWO examples of a chemical change.
Examples: rust, lighting a fire, fireworks, unexpected temperature or color change,
How many electrons does Chromium have?
How many hydrogen do I need on the right side in order to balance the equation?
2H2 + H02 -> ____H + 02
The left side has 5 hydrogen, so you would need 5.
2H2 + H02 -> 5H + 02
Draw a Bohr model for Iron.
1st: 2
2nd: 8
3rd: 16
What period is Cesium in on the periodic table?
6
Two clear liquids are mixed together and turn purple. Is this a chemical or physical change? Why?
Chemical change because it is an unexpected color change
How many neutrons does Silver have?
61 neutrons
In a chemical equation, what is the left side of the equation called?
Example: 2H2 + 20 -> 2H20 + H2
The reactants
What is wrong with this Bohr model?

1st: should have 2
2nd: should then have 1
do not need the 3rd level anymore
How many groups are on the periodic table?
18