The Atom Theory
Ernest Rutherford’s Gold Foil Experiment revealed that the atom is mostly made of this.
Empty space
This subatomic particle determines an element's identity.
Proton
Isotopes are atoms of the same element that have different numbers of these subatomic particles.
Neutrons
The atomic mass listed on the periodic table is a weighted average of all naturally occurring these.
Isotopes
On an NFPA 704 safety diamond, the top red section rates a chemical's hazard in this specific category.
This ancient Greek philosopher proposed the concept of "atomos," meaning indivisible.
Democritus
To find the number of neutrons in a neutral atom, you subtract the atomic number from this value.
Mass number
In the isotope name Carbon-14, the number 14 represents this specific total.
Mass number
If Element X has two isotopes—X-10 (90% abundance) and X-11 (10% abundance)—the average atomic mass will be closest to this whole number.
10
Trail mix, oil mixed with water, and muddy water are all examples of this type of mixture.
What is a heterogeneous mixture?
John Dalton pictured the atom as a solid, hard sphere—a model often compared to this game ball.
billard ball
An electron has almost negligible mass. In fact, its mass is approximately this fraction of 1 amu (or 1 proton).
1/2000 amu
How many neutrons are in an atom of Fluorine-19
10
A newly discovered element, "Xenonite," has an average atomic mass of 50.0 amu and consists of only two naturally occurring isotopes: X-48 (54% abundant) and X-51. What is the percent abundance of X-51?
46%
This piece of laboratory glassware with a flat bottom and narrow neck is ideal for swirling liquids without splashing.
Erlenmeyer flask
J.J. Thomson used cathode ray tubes to discover this subatomic particle.
Electron
If an atom loses 2 electrons, it is called this specific type of ion.
cation
Write the full nuclear symbol for an atom with 17 protons, 18 neutrons, and 17 electrons.
35Cl-
Before multiplying percent abundance by an isotope's mass in a calculation, you must divide the percentage by this number.
100
If a chemical splashes into a student's eyes in the lab, they should use the eyewash station for how many minutes?
20
Niels Bohr modified the atomic model by placing electrons into these fixed paths or energy levels.
Orbitals
An ion of an element has a mass number of 37 and a -1 charge. If this ion contains 18 electrons, how many neutrons does it have?
20
In both nuclear fission reactions, the total mass of the resulting particles is slightly less than the total mass of the starting subatomic particles.
1.)What is nuclear fission?
2. Explain what happens to this missing mass.
A process where the nucleus of a heavy atom splits into two or more smaller nuclei
It is converted into energy (E = mc2)?
To calculate an element's weighted average atomic mass, you must perform these three sequential mathematical steps using each isotope's mass and percent abundance.
Convert percentages to relative decimals (divide by 100), 2) Multiply each decimal by its isotope's mass, and 3) Add all the products together?
List three distinct signs that a chemical reaction (chemical change) has taken place.
What are color change, temperature/energy change, gas production (fizzing/bubbles), precipitate formation, or odor release?