What is the difference between a physical and chemical change?
a physical change is still the same substance, but a chemical change produces a whole new substance
100
What is the atomic number and what does it tell us?
the number of protons (and also electrons in a neutral atom)
100
What are elements in group 1 called and why are they special?
alkali metals- they have only one electron in their outer shell and are very reactive
100
What is the octet rule and how does it explain why atoms bond?
Most atoms want to have 8 electrons in their outer shell. They want to have a stable electron configuration and that is why they bond.
100
Name the following compound.
Lithium Astatide
200
Give an example of a physical change and an example of a chemical change.
varies
200
What is a mass number and what does it tell us?
the number of protons plus neutrons in an atom
200
What are elements in group 18 called and why are they special?
noble gases-they have full outer shells and are unreactive
200
Name 2 properties of ionic compounds.
hard, brittle, high melting point, conduct electricity when dissolved in water
200
Give the formula for the following compound.
dinitrogen trioxide
N2O3
300
What are 3 indications that a chemical change is occuring?
heat, gas produced, smell, color change, precipitate formed
300
If you have a neutral atom of cobalt, how many protons, neutrons, and electrons does it have?
27 protons and electrons 32 neutrons
300
What are elements in groups 3-12 called and why are they special?
transition metals- what people traditionally think of as metals, shiny, malleable, ductile, conduct electricity, can have multiple oxidation numbers
300
Name 2 properties of covalent compounds.
flexible, low melting point, do not conduct electricity when dissolved in water
300
Fe(NO3)2
Iron (II) nitrate
400
What is the difference between an element and a compound? Give an example of each.
an element is the smallest unit of a substance that still retains the properties of that substance, a compound is a combination of different elements chemically bonded together
400
Tell which subatomic particle each of the following statements is describing.
1. determines what an element is
2. determines how an element behaves in reactions with other elements
3. creates isotopes and can cause an element to be radioactive
1. proton
2. electron
3. neutron
400
What is the difference between a group and a period and what does each one tell us?
group-column-number of valence electrons
period-row-number of energy levels
400
Are the following compounds ionic or covalent?
Cl2, HCl, C6H12O6, CaCl2
covalent, ionic, covalent, ionic
400
What is the following type of reaction and what would the products be?
C3H8 + O2
combustion- CO2 and H2O
500
What is the difference between a homogenous mixture and a heterogeneous mixture? Give an example for both.
homogenous mixtures are mixtures where the substances that make up the mixture are uniformly distributed i.e. sweet tea, heterogeneous is not uniformly distributed i.e. muddy water
500
What are the 4 electron sublevels? What are their shapes and how many electrons can they hold?