Basics of chemistry

What is electric current?

The flow of electric charge.

What is the unit for electric current?

Amperes (A).

What do you measure current with? Where is it placed in the circuit?

Ammeter; placed in series.

What is potential difference?

The difference in electric potential energy per unit charge.

What is the unit for potential difference?

Volts (V).

What do you measure potential difference with? Where is it placed in the circuit?

Voltmeter; placed in parallel.

What is the difference between a series and a parallel circuit?

Series has one pathway, while parallel has multiple pathways.

How does current behave in a series circuit?

Current remains the same throughout the circuit.

How does current behave in a parallel circuit?

Current divides among the pathways.

What happens to the potential difference as resistance increases?

Potential difference increases.

What does the equation V = I × R represent?

The relationship between voltage (V), current (I), and resistance (R).

What factor increases the resistance in a wire?

Length of the wire.

What is the effect of a longer wire on current?

The current decreases.

Why does a wire heat up when made longer?

Increased collisions with metal ions result in heat.

How does higher resistance affect components in a circuit?

It limits the electricity each component receives.

Why might a high resistance be useful in a circuit?

It prevents overheating and allows control over current flow.

What is the atomic structure comprised of?

Atoms contain protons, neutrons, and electrons.

What is the charge of an atom's nucleus?

The nucleus has a positive charge due to the presence of protons.

What is an ion?

An ion is an atom or group of atoms that has lost or gained electrons.

How can you determine the number of neutrons in an atom?

Subtract the atomic number from the mass number.

What are isotopes?

Isotopes are different forms of the same element with the same number of protons but different numbers of neutrons.

What types of bonding occur in compounds?

Compounds can bond ionically (between metals and non-metals) or covalently (between non-metals).

What is a chemical equation?

A chemical equation shows the reactants on the left-hand side and the products on the right-hand side.

What does relative atomic mass take into account?

Relative atomic mass accounts for the different isotopes of an element and their abundances.

How does the modern periodic table arrange elements?

Elements are arranged by increasing atomic number.

What is the typical maximum number of electrons in the first three shells?

2 electrons in the first shell, 8 in the second, and 8 in the third shell.

What is the difference between metals and non-metals?

Metals are strong, malleable, and good conductors, while non-metals are dull, brittle, and poor conductors.

What is the formula for carbon dioxide?

The formula for carbon dioxide is CO₂.

Who is credited with creating the modern periodic table?

Dmitri Mendeleev is credited with creating the modern periodic table.

What happens to the reactivity of alkali metals as you go down the group?

The reactivity of alkali metals increases as you go down the group.

What are chemical equations fundamental to?

Chemistry.

What are the molecules on the left-hand side of a chemical equation called?

Reactants.

What are the molecules on the right-hand side of a chemical equation called?

Products.

What must always be true about atoms in a balanced chemical equation?

There must always be the same number of atoms on both sides.

What method separates soluble solids from solutions?

Crystallisation and evaporation.

What is chromatography used for?

To separate different substances in a mixture.

What is the method called that separates mixtures containing liquids?

Distillation.

Who proposed the 'plum pudding' model of the atom?

JJ Thomson.

What did Rutherford's gold foil experiment demonstrate?

That atoms have a small, positively charged nucleus.

What was Bohr's contribution to atomic structure?

Proposed that electrons orbit the nucleus in fixed shells.

What are the four states of matter?

Solid, liquid, gas, plasma.

What does 'aqueous' (aq) mean in chemistry?

It refers to a solution where a solid and liquid are dissolved together.

What type of reaction results in the production of salt and water?

Acid + Metal oxide → salt + water.

What is the word equation for the reaction between a base and an acid?

Base + Acid → Salt + Water.

What is required for a solution to be considered acidic?

It must contain a high concentration of hydrogen ions.

What is the name of the salt formed when magnesium and hydrochloric acid react?

Magnesium chloride.

What safety precaution is recommended when conducting experiments?

Wearing safety goggles.

What does it mean for a base to be soluble?

It can dissolve in water.

What is the result of adding copper oxide to sulfuric acid?

Copper sulfate and water are produced.

How can you improve the clarity of a practical lab method?

By adding specific measurements and using scientific vocabulary.

What type of bond is formed when alkali metals transfer electrons to halogens?

Ionic bond.

What type of bond is formed between two halogen atoms?

Covalent bond.

Which group of elements are gases at room temperature in the context of the lecture notes?

Group 7 elements (halogens).

At what temperature is considered room temperature for this context?

20 degrees Celsius.

If a substance has a melting point higher than 20 degrees Celsius, what state of matter is it at room temperature?

Solid.

What do we infer if a substance has a boiling point lower than 20 degrees Celsius?

It is a gas at room temperature.

Which element was mentioned to have a melting point higher than 20 degrees Celsius?

Iodine.

What does relative molecular mass indicate about a molecule?

The size of the molecule.

As the relative molecular mass increases, what happens to the size of the atoms?

The atoms get bigger.

Atom

Smallest piece of an element that can exist.

Chemical equation

Shows what happens in a chemical reaction using symbols or words.

Reactants

Chemicals that are reacting with eachother.

Where are reactants found?

On the left side of equations.

Products

Chemicals that are being made.

Where are products found?

On the right side of equations.

Word equation

Equation using words

Symbol equation

Equation using chemical symbols.

Name a mandatory feature of a symbol equation

Must be balanced

What are the main groups of elements in the periodic table?

Alkali metals, Noble gases, Halogens, Transition metals.

Where are metals and non-metals located in the periodic table?

Metals are located to the left of the periodic table, while non-metals are on the right.

What charge do alkali metals typically form?

Alkali metals generally form +1 ions.

What is the trend of reactivity in alkali metals down the group?

Reactivity increases down the group.

What was Mendeleev known for in the development of the periodic table?

Mendeleev arranged elements by atomic weight and left gaps for undiscovered elements.

What is the electronic structure of sodium?

The electronic structure of sodium is 2, 8, 1.

How many electrons can the first, second, and third shells hold?

1st shell: 2 electrons; 2nd shell: 8 electrons; 3rd shell: 8 electrons.

What makes an atom more likely to react?

An atom with an outer shell that is not full is more likely to react to fill it.

What is the electronic structure of nitrogen?

The electronic structure of nitrogen is 2, 5.

What is the electronic structure of magnesium?

The electronic structure of magnesium is 2, 8, 2.