Atoms & Elements
Fill in the blank: The correct chemical name for the element with the symbol Na is __________.
Sodium
Bonus Question for Extra Points (50 points): Look closely at how the symbol for Sodium is written (Na). What is the strict rule in science about using capital and lowercase letters when writing a two-letter chemical symbol?
Where can you find Alkali Metals located on the table?
A) In a horizontal row right across the middle.
B) In the very first vertical column on the far left side (Group 1).
C) In the very last column on the far right side (Group 0/8).
D) Floating in a separate block at the very bottom
Correct Answer: B
Explanation: The Alkali Metals make up Group 1, which is the very first vertical column on the left side of the Periodic Table (excluding Hydrogen at the top).
How would a scientist classify salt water?
A) As a pure element, because it is all liquid.
B) As a compound, because the salt has permanently turned into salt water compound.
C) As a mixture, because the salt and water are just physically mingled together.
D) As an atom, because it tastes salty.
Correct Answer: C
Explanation: Salt water is a mixture. The salt and water are thoroughly mixed together, but they haven't chemically reacted to form a completely new substance.
Name one physical property of metals.
Shiny / Lustrous: They reflect light well when polished or freshly cut.
Good conductors of electricity: They allow electrical currents to pass through them easily.
Good conductors of heat: They allow thermal energy to pass through them quickly (e.g., why a metal spoon gets hot in soup).
High melting points / Boiling points: They are usually solid at room temperature and require massive amounts of heat to melt (with Mercury being the famous exception).
Malleable: They can be hammered, bent, or rolled into flat sheets without snapping or shattering.
Ductile: They can be drawn or stretched out into long, thin wires (like copper wiring).
High density / Heavy: They feel heavy for their size because their atoms are tightly packed together.
Sonorous: They make a clear, ringing, bell-like sound when you hit them.
Question: Group 0 (sometimes called Group 8) sits on the very far right side of the Periodic Table and includes gases like Helium, Neon, and Argon. What is the most famous chemical property of this family of elements?
A) They explode violently when touched by a single drop of water.
B) They are completely unreactive (they do not easily bond or react with anything).
C) They are highly acidic liquids that can melt through metal desks.
D) They are the heaviest solids on earth.
Correct Answer: B
They are completely unreactive (they do not easily bond or react with anything).
What is the definition of an element?
A pure substance made up of only one type of atom.
Bonus Question for Extra Points (50 points): Water has the chemical formula H2O. Based on our definition of an element, explain why water is not listed on the Periodic Table.
Statement: Alkali metals like Sodium and Potassium are also incredibly hard and can only be cut using a heavy-duty industrial saw.
Is this statement TRUE or FALSE?
Correct Answer: FALSE
Explanation: Alkali metals are unusually soft! In fact, they are so soft that you can easily cut them in half in the lab using a simple plastic or butter knife.
Statement: Clean, fresh air is a pure chemical compound because all the different gases are permanently bonded together into a single "air molecule."
Is this statement TRUE or FALSE?
Correct Answer: FALSE
Explanation: Air is a mixture of completely separate gases (mostly Nitrogen and Oxygen, with a tiny bit of Argon and Carbon Dioxide) floating around freely next to each other.
👉 BONUS QUESTION FOR EXTRA POINTS (50 points): Which gas makes up the biggest part of our atmosphere, taking up roughly 78% of the air mixture?
Name one chemical property of metals.
Tarnishing or rusting (e.g., iron reacts with oxygen and water to form rust).
Fizzing, moving, or exploding when dropped in water (especially the Group 1 Alkali Metals).
Flammable / can burn: Some metals, like magnesium ribbon, can burn with a bright white light when heated.
Unreactive: Precious metals like gold and platinum do not react easily with water, acids, or oxygen (which is why they stay shiny forever).
Question: Group 7 on the Periodic Table contains a group of non-metal elements called The Halogens, which includes Fluorine, Chlorine, Bromine, and Iodine.
Statement: As you look down the Group 7 column, all of these elements exist as clear, colorless, odorless gases at room temperature.
Is this statement TRUE or FALSE?
Correct Answer: FALSE
The Halogens are famous for having different states and vivid colors! Chlorine is a green gas, Bromine is a dark red liquid, and Iodine is a dark purple/grey solid.
Statement: The negatively charged electrons exist inside the nucleus of the atom.
Is this statement TRUE or FALSE?
FALSE
The tiny electrons actually orbit on the outside of the nucleus in layers called shells.
Alkali metals are famous for how intensely they react with water. If you drop a small piece of Lithium or Sodium into water, what will you physically see happening?
It will float, fizz rapidly, move across the surface, and eventually disappear.
Alkali metals react vigorously, releasing hydrogen gas which causes them to fizz and whiz across the surface.
Statement: You buy a bottle of "Still Mineral Water" from the shop. The label says "100% Pure Natural Water," but when you turn the bottle around and look at the ingredients, it lists tiny amounts of Calcium, Magnesium, and Sodium dissolved inside it.
Answer: It is technically a ______________.
Correct Answer: Mixture
Explanation: In everyday language, "pure" means clean or natural. But in chemistry, a "pure substance" means it contains absolutely nothing but one type of particle. Because mineral water has dissolved mineral atoms floating amongst the water molecules, it is a mixture!
Question: Copper is the most common material used to make the electrical wiring inside our home appliances and walls. Which physical property of metals makes copper perfect for this job?
A) It is highly magnetic.
B) It is a good conductor of electricity.
C) It has a very bright orange color.
D) It dissolves easily when it gets wet.
Correct Answer: B
Explanation: Metals are excellent electrical conductors because they allow electrical energy to flow through them smoothly without stopping.
Question: Group 7 elements are known as "The Halogens". Which of the following elements belongs to this highly reactive non-metal family?
A) Sodium
B) Helium
C) Chlorine
D) Iron
Correct Answer: C
Explanation: Chlorine is a famous member of Group 7. Sodium is a Group 1 metal, Helium is a Noble Gas, and Iron is a transition metal.
What is the name given to the horizontal rows that go across the table from left to right of the Periodic Table?
The table goes side-to-side in Periods (which tell you how many electron shells an atom has) and up-and-down in Groups (which cluster elements with similar chemical properties together).
What happens to the shiny surface of a freshly cut alkali metal if it is left exposed to the air for just a few minutes?
It goes dull / tarnishes (because it reacts with the oxygen in the air).
Table salt, water, and carbon dioxide are all common substances we use every day. How would a scientist classify all three of these substances?
As elements, compounds or mixtures?
Explanation: All three are compounds because they are made of different types of atoms (such as Sodium and Chlorine for salt) that are chemically bonded together.
Question: Most metals have very high melting points, which means they stay solid even when heated to high temperatures over a Bunsen burner.
Statement: Every single metal on the Periodic Table is a solid at normal room temperature.
Is this statement TRUE or FALSE?
Correct Answer: FALSE
Explanation: There is one famous exception: Mercury is a metal, but its melting point is so low that it exists as a liquid at room temperature!
Question: Group 8 (also known as Group 0) is a famous family of gases on the very far right side of the Periodic Table. What is the special name given to this family?
The Noble Gasses
Statement: An element can be easily chopped, heated, or chemically broken down into a simpler chemical substance.
Is this statement TRUE or FALSE?
FALSE
Explanation: Elements are already in their simplest possible form. You cannot break them down into anything simpler by chemical means.
As you move down the Group 1 column from Lithium to Sodium and then to Potassium, the atoms get larger. What happens to how violently these metals react as you go further down the group?
As you go down the group, the reactivity __________.
Increases (or gets more violent / stronger)
Question: The names of chemical compounds tell us exactly which elements were mixed together and chemically bonded to make them. For example, the compound sodium chloride (table salt) is made from the metal Sodium and the non-metal Chlorine.
Look at the names of the two everyday compounds below and write down the two elements that make up each one:
Lithium oxide is made of __________ and __________.
Iron sulfide is made of __________ and __________.
Correct Answer: 1. Lithium and Oxygen 2. Iron and Sulfur
Explanation: When elements combine, the metal keeps its name, but the non-metal's name changes its ending to "-ide". So, oxygen becomes oxide and sulfur becomes sulfide.
Explain the difference between a physical property and a chemical property of a metal.
Possible answers:
"A physical property can be observed without changing what the material is made of, but a chemical property tells you how a substance changes into a completely brand-new substance."
"Physical properties (like melting or bending) can usually be undone or reversed. Chemical properties involve chemical reactions, which are very difficult or impossible to reverse."
"Physical properties are things you can just see or measure by looking at it (melting). Chemical properties require you to actually try and react the metal with something else to see what happens."
Question: Helium is a Group 8/0 Noble Gas used to fill party balloons so that they float up in the air.
Statement: Helium gas is chosen for party balloons because it is highly explosive and will burst into flames if a candle gets near it.
Is this statement TRUE or FALSE?
Correct Answer: FALSE
Explanation: Helium is completely unreactive, meaning it is totally safe and will never catch fire or explode.