Year 9 Chemistry

What are electrons?

• Negatively charged particles that orbit the nucleus of an atom.

• Positively charged particles found in the nucleus of an atom.

• Neutral particles that float freely in space.

• Particles that are responsible for the mass of an atom.

What are the positive particles of an atom?

• Neutrons

• Electrons

• Protons

• Nuclei

What is the atomic number?

• The number of neutrons in an atom

• The number of protons in the nucleus of an atom

• The total number of electrons in an atom

• The mass of an atom in atomic mass units

What is the periodic table?

• A tabular arrangement of elements organized by atomic number, electron configuration, and recurring chemical properties.

• A graphical representation of chemical reactions.

• A list of all known chemical compounds.

• A collection of isotopes of various elements.

What charge does an atom have after losing one electron?

• 0

• -1

• +1

• +2

What is the charge of a neutron?

• Positive charge

• Negative charge

• No charge; they are neutral particles.

• Variable charge depending on the environment

What does the toxicity of a substance refer to?

• The toxicity of a substance refers to how it affects your health.

• The toxicity of a substance refers to its chemical composition.

• The toxicity of a substance refers to its physical state.

• The toxicity of a substance refers to its cost and availability.

What is an ion?

• An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

• A type of molecule that is always neutral in charge.

• A particle that cannot gain or lose electrons.

• A solid substance that conducts electricity.

What is the nucleus of an atom?

• The outer shell of an atom that contains electrons.

• The central part of an atom, containing protons and neutrons.

• A type of particle that orbits the nucleus.

• The energy level of an atom.

What is a chemical reaction?

• A process that leads to the transformation of one set of chemical substances to another.

• A method of separating mixtures into their individual components.

• A technique used to measure the pH of a solution.

• A way to combine different elements without changing their properties.