Atomic Structure & Elements
Periodic Table & Isotopes
Chemical Bonds
Water Properties
Acids, Bases & pH
100
What is the smallest unit of matter that makes up an element?
Atom.
100
What is an element?
A substance that cannot be broken down into simpler chemical substances.
100
What are the two main types of chemical bonds?
Ionic and covalent bonds.
100
What property of water allows it to stick to itself?
Cohesion.
100
What does pH stand for?
Potential Hydrogen
200
Name the three subatomic particles and their charges.
Proton (+), Neutron (neutral), Electron (-).
200
What are isotopes? Give an example.
Isotopes are atoms of the same element with different numbers of neutrons, e.g., Carbon-12 and Carbon-14.
200
Balance the following equation:
200
What kind of bond forms between water molecules?
Hydrogen bond.
200
What is the impact of ocean acidification?
It reduces the pH of the ocean, harming marine life.
300
What determines the atomic number of an element?
The number of protons.
300
How many protons and neutrons does Carbon-14 have?
6 protons and 8 neutrons.
300
What is a covalent bond?
A bond formed when two atoms share electrons.
300
What is a solution?
A mixture where one substance (solute) is dissolved in another (solvent)
300
If a solution containing 300,000 atoms contains 300 H+ ions, what is the pH of the solution?
pH=3
400
Where are protons and neutrons located in an atom?
In the nucleus.
400
How are isotopes used in science?
They are used in radiometric dating and cancer treatment.
400
How many covalent bonds can hydrogen form?
One
400
What is capillary action, and how does it relate to water?
The ability of water to move up narrow tubes, like in plant roots, due to cohesion and adhesion.
400
What is the color change of litmus paper in an acidic solution?
Red
500
What is the difference between atomic number and atomic mass?
Atomic number is the number of protons; atomic mass is the total of protons and neutrons.
500
A scientist has a sample of a radioactive substance with a half-life of 10 years. If the original amount of the substance is 100 grams, how much of the substance will remain after 30 years?
After 30 years, 12.5 grams of the substance will remain.
After 10 years:
100 grams ÷ 2 = 50 grams
After 20 years:
50 grams ÷ 2 = 25 grams
After 30 years:
25 grams ÷ 2 = 12.5 grams
500
What type of bond holds the oxygen and hydrogen atoms together in a water molecule?
Polar covalent bond.
500
What is the difference between a solvent and a solute?
The solvent dissolves the solute.
500
What is the typical pH range that pH paper can test?
From 0 to 14.
600
What is the charge of an atom that loses an electron? What do we call this atom now?
+1 charge and it is called a cation.
600
A fossil contains 80 grams of carbon-14. The half-life of carbon-14 is 5,730 years. How much carbon-14 will remain in the fossil after 22,920 years
After 22,920 years, 5 grams of carbon-14 will remain in the fossil.
After 1 half-life (5,730 years):
80 grams ÷ 2 = 40 grams
After 2 half-lives (11,460 years):
40 grams ÷ 2 = 20 grams
After 3 half-lives (17,190 years):
20 grams ÷ 2 = 10 grams
After 4 half-lives (22,920 years):
10 grams ÷ 2 = 5 grams
600
What kind of bond forms between the 2 carbon atoms?
How many double bonds are in this molecule?
How many single bonds?
Draw the Structural Formula
Double bond between the carbons.
One double bond overall.
four single bonds.
600
How does water dissolve ionic compounds like salt?
The positive side of water attracts the anions, and the negative side attracts the cations.
600
What happens to the pH when CO₂ dissolves in water, and how can indicators show this change?
The pH decreases, becoming more acidic, and indicators like bromothymol blue can change from blue to yellow, signaling increased acidity.