Matter
Atomic Structure
Periodic Table
Chemical Reactions
Acids and Bases
100

This state of matter has a definite volume but takes the shape of its container.

What is a liquid?

100

These negatively charged subatomic particles occupy the space outside an atom's nucleus

What are electrons?

100

This family of highly reactive metals occupies Group 1 of the periodic table and includes sodium and potassium.

What are the alkali metals?

100

In this type of reaction, two or more simple substances combine to form a single, more complex product.

What is a synthesis (or combination) reaction?

100

This logarithmic scale ranges from 0 to 14 and is used to specify how acidic or basic an aqueous solution is.

What is the pH scale?

200

The phase transition where a solid turns directly into a gas without becoming a liquid first.

What is sublimation?

200

Atoms of the same element that have the same number of protons but different numbers of neutrons.

What are isotopes?

200

This Russian chemist is widely credited with publishing the first recognizable periodic table in 1869, famously leaving gaps for undiscovered elements.

Who is Dmitri Mendeleev?

200

These starting substances are written on the left side of a chemical equation and are consumed during the course of the reaction.

What are reactants?

200

According to the Brønsted-Lowry definition, an acid acts specifically as a donor of this subatomic particle.

What is a proton (or hydrogen ion / H⁺)?

300

This type of mixture is completely uniform in composition throughout, like clean air or salt water.

What is a homogeneous mixture (or solution)?

300

He proposed the "plum pudding" model of the atom after discovering the electron using a cathode ray tube.

Who is J.J. Thomson?

300

These elements occupy Group 18 and are famously unreactive due to having a full valence shell of electrons.

What are the noble gases?

300

A chemical reaction that releases net thermal energy into its surroundings, often causing the temperature of the immediate environment to rise.

What is an exothermic reaction?

300

This type of household cleaner component generally turns red litmus paper blue, tastes bitter, and feels slippery to the touch.

What is a base?

400

A characteristic of a substance that can be observed or measured without changing the substance's chemical identity, such as density or boiling point.

What is a physical property?

400

This incredibly dense, positively charged region at the center of the atom contains almost all of its mass.

What is the nucleus?

400

This periodic trend describes an atom's relative ability to attract shared electrons toward itself within a chemical bond.

What is electronegativity?

400

This type of rapid reaction involves a substance reacting with oxygen gas, typically generating carbon dioxide, water, and flame.

What is a combustion reaction?

400

The specific name for a double-replacement reaction between an acid and a base that produces water and an ionic salt.

What is a neutralization reaction?

500

This fundamental law states that mass is neither created nor destroyed during a chemical reaction.

What is the Law of Conservation of Mass?

500

This quantum mechanics principle states that it is impossible to simultaneously know both the precise position and momentum of a particle.

What is the Heisenberg Uncertainty Principle?

500

Due to an increasing effective nuclear charge drawing electrons closer, this atomic measurement decreases as you move from left to right across a period.

What is atomic radius?

500

This term describes the ions that do not participate in the actual chemical change of a reaction and appear unchanged on both sides of a total ionic equation.

What are spectator ions?

500

This term describes a unique substance, such as water, that has the ability to act as either an acid or a base depending on the environment.

What is amphoteric?