These properties can only be observed when a compound's identity is changed.
What are chemical properties?
100
This is the formula for density.
What is D = m/V?
100
This number corresponds to the number of energy levels and element has (in its Bohr model).
What is the period number? (periods go from side to side, there are 7)
100
A charged atom.
What is an ion?
100
An element that has the same number
of valence electrons as krypton (Kr)?
What is neon, argon, xenon, or radon? (they are in group 18 & all in group 18, except helium, have 8)
200
Examples are melting point, mass, boiling point and density.
What are physical properties?
200
Ice floats because its density is _______ than the density of liquid water.
What is less?
200
This is the name of the group that includes the elements calcium and strontium.
What are the alkaline earth metals? (group 2)
200
The name of atoms that have gained electrons & their charge.
What are anions & negative?
200
If the melting point of a substance is -120 C and the boiling point is 50 C, it will be this phase at -105 C.
What is liquid? (-105 C is above the melting point - so it is not frozen - and is below the boiling point - so it is not a gas)
300
Phase changes are this type of change.
What are physical? (if you melt ice, you still have H2O)
300
This is the density of a 3 g ball that is placed in a graduated cylinder. Before adding the ball, the volume of the water was 2 mL. After adding the ball, the volume on the cylinder was 17 mL.
What is 0.2 g/mL? (the ball has a volume of 15 mL; divide mass (3 g) by the volume (15 mL))
300
What is an element that would have similar properties to oxygen?
What is (any one of the following) sulfur, selenium, tellurium, polonium? (elements in the same group (family) act alike)
300
The sign and number of the charge an atom in group 2 will take on.
What is +2? (group 2 metals will lose 2 electrons, giving them a positive charge of 2)
300
A reaction takes place in a beaker and the beaker feels hot to the touch. This reaction would be called endo- or exothermic?
What is exothermic? (if it feels hot, then it is giving off heat - think about your stems!!)
400
Examples are burning, rusting and spoiling.
What are chemical changes?
400
Densities of gemstones (g/mL):
OPAL ----- 2.20
TOPAZ ----- 3.50
GARNET ----- 3.15
DIAMOND ----- 3.01
A stone has a mass of 6.24 g and a volume of 1.98 mL. What is the identity of the stone?
What is garnet? (divide D=m/V and get 6.24/1.98 = 3.151515)
400
Elements that fall on the stair step line & have properties of both metals and non-metals.
What are the metalloids?
400
Nonmetals do this (gain electrons or lose electrons) when they become ions and get this charge (positive or negative).
What is gain electrons and become negative.
400
On a heating curve these lines represent single phases (flat or diagonal).
What is diagonal? See diagram #1b.
500
The four evidences of a chemical change.
What are color change, production of a gas (bubbles), production of a precipitate, and giving off or taking in heat and/or light.
500
The density of water.
What is 1 g/mL?
500
This number determines the number of valence (outermost) electrons in an atom.
What is the group number? (group # equals the number of valence electrons - if it is a "teen" group, ignore the one EX: group 15 has 5)
500
The charge of a nonmetal ion in group 15.
What is -3? (Group 15 has 5 valence electrons, so they need to gain 3 more to get to 8; this gives them a surplus of 3 negative charges; -3)
500
The six phase changes & what they change to & from.
Ex: freezing is liquid to solid
(Now you only have 5 more!)
What are the following:
melting is solid to liquid
vaporization is liquid to gas (boiling & evaporation are forms of this)
condensation is gas to liquid
sublimation is solid to gas
deposition is gas to solid