Unit 2 Review
TRUE or FALSE Salt (NaCl) is a pure substance and an element.
ANSWER False… pure substance and compound. Two elements combined = compound
Which state of matter would take the shape of it’s container and has a fixed/definite volume?
ANSWER Liquid
A popsicle melting on the sidewalk is an example of what type of change?
ANSWER Physical…all phase changes (solid liquid gas) are physical changes.
“A shiny piece of steel rusted from sitting out in the rain.” Which part of this statement represents a physical property? Which part represents a chemical property?
ANSWER “A shiny piece of steel rusted from sitting out in the rain.” “SHINY” is physical, describing what it looks like “RUSTING” is chemical, because rust has a different composition than steel.
Matter changing from its liquid state to its gaseous state is called ______.
ANSWER Vaporization Boiling Evaporation
What is an ion?
ANSWER An atom with a positive or negative charge. An atom that has lost or gained electrons.
If at ion has a positive charge, did it GAIN electrons or LOSE electrons?
ANSWER LOSE electrons so that the there are now more positive protons than there are negative electrons.
How many neutrons does Carbon-14 have?
ANSWER 14 is the mass number of that particular isotope of Carbon and the atomic number of Carbon is 6, so 14-6= 8 neutrons.
TRUE or FALSE To get an isotope, you fluctuate the number of electrons.
ANSWER FALSE. You would fluctuate the number of neutrons to change the mass.
Who discovered protons? LAST NAME, HOW?
ANSWER Ernest Rutherford by shooting alpha particles (positive particles) at a piece of foil. The alpha particles deflected, which showed they were hitting something else that was positive (protons).
Who came up with the first atomic theory?
ANSWER John Dalton
Who discovered electrons and how? LAST NAME
ANSWER JJ Thomson- cathode ray tube showed electrons are emitted. Negative side of magnet repelled (or positive side attracted) so proved they were negative.
What part of the atom gives it it’s identity?
ANSWER Protons
Would spaghetti be a pure substance or a mixture?
ANSWER Mixture (heterogeneous)
What are the 3 particles of the atom and their respective charges?
ANSWER Proton + Neutron (neutral) Electron -
Why isn’t the mass of strontium-92 on the periodic table reported as 92?
ANSWER The periodic table shows average atomic masses of all isotopes present
How many electrons fit on energy level 1, 2,& 3?
ANSWER 1st holds 2 2nd holds 8 3rd holds 8
Who created the atom model where electrons are found on energy levels?
ANSWER Niels Bohr
Draw the Bohr diagram for phosphorus.
ANSWER 15 P 16 N 15 E
Write the following info in isotopic notation Protons- 26 Neutrons- 31 Electrons- 23
ANSWER 57Fe3+ 26
Atomic Number Mass Number Neutrons Electrons
ANSWER Atomic Number- 16 Mass Number- 33 Neutrons- 17 Electrons -18
Who discovered the neutron?
ANSWER James Chadwick
Protons-20 Electrons-20 Neutrons-22 Isotope name?
ANSWER Calcium-42
Protons-20 Electrons-20 Neutrons-22 Give the correct notation.
ANSWER
What is the name of the element if the only information you have is there are 35 protons?
ANSWER Bromine
List techniques for physically separating a mixture (think about our lab)
ANSWER Filtering Using a magnet Boiling Dissolving