Chemical vs. Physical
True or false? The change of state (ex. melting) is a chemical change.
FALSE !! That is a physical change
Non-metal + metal & TRANSFER electrons
What is a molecular / covalent compound?
Non-metals only & SHARE electrons
What are valence electrons?
Electrons on the outermost shell
What is an atom?
Has mass and takes up space
When milk goes bad in the fridge, is that an example of a physical or chemical change?
CHEMICAL !! cannot reverse & new substance (bacteria) is formed
What is the name for compound Li₃P?
(hint: determine if it is ionic or molecular first)
Lithium phosphide
What is the name of the compound N₂S₃?
Dinitrogen trisulfide
What is the octet rule?
All elements need 8 electrons in their valence shell to become stable (hydrogen only needs 2)
List the 3 subatomic particles and their charges.
Electrons = negative (-)
Protons = positive (+)
Neutrons = neutral (0)
If you cut down a tree into logs... is that a chemical or physical change?
PHYSICAL !! no new substance is formed, only cutting it into smaller pieces
What is the name for the compound Fe₂Se₃?
(hint: add roman numerals to Fe)
Iron (III) Selenide
What is the name of the compound HBr?
(hint: determine if it is ionic or molecular first)
Hydrogen monobromide
What is the difference between a cation and anion?
Cations are positive
Anions are negative
What are the locations of protons, electrons, and neutrons?
Proton & neutron = inside nucleus
Electron = orbits around nucleus
List 2 evidence of a chemical change.
change in colour, temperature, or smell
production of gas, precipitate, or light
What is the formula for potassium oxide?
K₂O
What is the formula for carbon tetrafluoride?
CF₄
Do metals lose or gain electrons?
Do non-metals lose or gain electrons?
Metals = LOSE
Non-metals = GAIN
What are the masses of protons, electrons, and neutrons?
Proton = 1
Neutron = 1
Electron = 0
What is the difference between a physical and chemical change?
chemical CANNOT be reversed, physical can be reversed
What is the formula for magnesium nitride?
Mg₃N₂
What is the formula for diboron hexahydride?
B₂H₆
Why are the noble gases non-reactive?
They already have a full valence shell & are stable
What is the atomic theory of matter?
All matter is made of elements
Different elements = different properties
Same element = similar properties
Different elements combine in certain ways to form new substances