Electricity and Chemistry Exam Review

Electricity

The flow of electrons through a conductor

Current (I)

The electron flow caused when electrons move through a conductor and carry electrical energy from one place to another

Current Measurement

Ammeter

Unit of Current

Amperes/Amps (A)

Voltage (V)

The measure of potential energy per unit of charge supplied by a source.

Voltage Measurement

Voltmeter

Unit of Voltage

Volts

Voltage Drop

The loss of potential energy when it flows through a component in a circuit

Resistance (r)

The measure of how much a component slows down the flow of electrical charge / Opposes the flow of current.

Resistance Measurement

To find the resistance, you need to use Ohm's Law. You also need to know the voltage and current in the circuit.

Unit of Resistance

Ohms (Ω)

Ohm's Law

V = I x R; Voltage = Current x Resistance

Series Circuit

A single loop where all circuit components are present - switch, battery, and bulb.

Resistance in Series Circuit

Voltage increases with the resistance (directionally proportional), current always stays the same in a series circuit.

Parallel Circuit

A circuit with more than one branch/loop of wire and each branch has circuit.

Current and Voltage in Parallel Circuit

Current is split between each branch while voltage is the same in every branch.

Resistance in Parallel Circuit

Current decreases (inversely proportional) while voltage stays the same since it's not affected by resistance in a parallel circuit.

Voltage in Parallel Circuit

The voltage is split equally between each bulb.

Factors Affecting Electricity

Wire length, wire thickness, and wire material.

Conductor

A material that easily allows the electrical current to flow through. A material that has low resistance. Examples are silver, copper, and aluminium.

Insulator

A material that doesn't easily allow the electrical current to flow through. It has high resistance. Examples are rubber, wood, plastic and glass.

Current and Resistance Relationship

Inversely proportional.

Current and Voltage Relationship

Directly proportional.

Number of Neutrons Calculation

Mass number - Atomic number.

Strong Nuclear Force

The attractions between the protons in the nucleus and the electrons in the electron shell. It holds the atom together.

Groups in the Periodic Table

Sorted by how many electrons in outermost shell - vertical.

Periods in the Periodic Table

Sorted by how many electron shells in total - horizontally.

Properties of Metals

Lustrous, malleable, ductile, good conductors of heat and electricity.

Properties of Non-Metals

Brittle, dull, poor conductors of heat and electricity.

Properties of Metalloids

Mixture of metals and non-metals; can be shiny, can be dull, they can be good conductors of heat and electricity but not as much as metals.

Ions

Atoms that lose or gain electrons to have a full valence shell.

Cations

Atoms that lose electrons, they have an overall positive charge.

Anions

Atoms that gain electrons, they have an overall negative charge.

Isotopes

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

Radioactivity

Radioactive decay that happens when an unstable nucleus emits radiation to achieve stability.

Ways of Nuclear Decay

Alpha, Beta and Gamma.

Alpha Decay

When the nucleus ejects an alpha particle (2 neutrons, 2 protons - overall positive charge) - this happens when there is a large amount of mass.

Beta Decay

Nucleus ejecting a beta particle (electron - negative charge) or a neutron converts into a proton and electron.

Gamma Decay

Doesn't emit particles - instead emits electromagnetic rays (gamma rays). The protons and neutrons rearrange in the nucleus.

Half-Life

The time taken for half of all the nuclei in a sample to decay.