Grade 9 IB Exam Review

What charge do metals typically have according to the periodic table?

Metals have a positive charge.

What is the key characteristic of alkali metals?

Alkali metals are highly reactive, especially with water.

Which group contains elements like Beryllium and Calcium?

Group 2 contains alkaline earth metals including Beryllium and Calcium.

What are noble gases known for?

Noble gases are unreactive due to having a full valence electron shell.

What does the particle theory of matter state?

All matter is made up of small particles that are always moving.

Define physical properties of a substance.

Physical properties can be observed and measured without changing the identity of the substance.

What occurs in a chemical reaction?

A substance changes or reacts to form new substances.

What is the result of the glowing splint test?

The gas produced rekindles a glowing splint, indicating the presence of oxygen (O2).

Who proposed the theory that atoms are indivisible?

Democritus proposed that atoms are indivisible.

What did J.J. Thomson discover?

J.J. Thomson discovered electrons using cathode rays.

What is required to ionize a metal?

Check if it is a metal or nonmetal; metals lose electrons while nonmetals gain electrons.

What is the formula to calculate efficiency?

Efficiency = Useful Energy / Total Energy x 100.

What defines a producer in an ecosystem?

A producer, or autotroph, is an organism that can create its own food, like grass.

Explain the nitrogen cycle in brief.

The nitrogen cycle includes processes like nitrogen fixation, nitrification, and the involvement of various bacteria.

What is biomagnification?

Biomagnification is the increase in concentration of a chemical as it moves up the food chain.

What happens during photosynthesis?

Photosynthesis converts light energy into chemical energy stored as glucose.

What is the Big Bang Theory?

The Big Bang Theory describes the universe's origin from a hot and dense state about 13.8 billion years ago.

What are supernovas?

Supernovas are massive explosions that occur when a star runs out of nuclear fuel.

How is a black hole formed?

A black hole is formed from the remnants of a massive star after a supernova explosion.

Define static electricity.

Static electricity is the buildup of electric charge on the surface of objects.

What happens in series vs. parallel circuits regarding voltage and current?

In series, voltages add up while currents are the same; in parallel, voltages are the same while currents add up.