G6 Unit 2 - Particles

Particles

solid

state of matter solid

​The particles in solids are very close together, therefore they cannot usually be compressed or squashed. Forces of attraction between the particles hold them together and keep them in place.

The particles in solids are arranged in a regular way. The particles in solids move only by vibrating about a fixed position. This gives solids a fixed shape and means that they cannot flow like liquids.

The hotter a solid gets, the faster its particles vibrate. This means that solids expand when they are heated.

liquid

state of matter: liquid

The particles in liquids are arranged in a random way, and are close together, touching many of their neighbours. There are some gaps, but liquids cannot usually be compressed or squashed.

The particles of a liquid have enough energy to break free of some of the forces of attraction between the particles. So particles in liquids can move around and can move over each other, allowing liquids to flow and be poured.

gas

state of matter: gas

The particles in gases are widely spaced and randomly arranged, meaning they can be easily compressed or squashed.

The particles in a gas have enough energy to overcome the forces of attraction between the particles, so are free to move in any direction. They move quickly in straight lines, colliding with each other and the walls of their container.

Why is helium gas used inside party balloons?

Helium gas is lighter than the mixture of gases that make up air. The lighter helium gas is trying to move above the air making the balloon rise up

Did you know?

Multiple Choice

Which state of matter has particles which are arranged in a regular way?

• solid

• liquid

• gas

Multiple Choice

How do particles in a solid move?

• Move fast in straight lines

• Move freely

• Vibrate

• Are stationary

Multiple Choice

Which substance can be easily compressed?

• Solid

• Liquid

• Gas

Multiple Choice

What happens to solids when they are heated?

• They break down

• They expand

• They freeze

• They contract and get smaller

Multiple Choice

How do particles in a liquid move?

• Move fast in curved path

• Move fast in straight lines

• Vibrate

• Move freely over each other

Multiple Choice

What happens to a balloon filled with helium?

• It sinks

• It floats

• It changes colour

Multiple Choice

How are the particles in a brick arranged?

• Regularly arranged

• Randomly arranged

Multiple Choice

What is the state of matter in this image?

• Solid

• Liquid

• Gas

Multiple Choice

Which state of matter is represented in this diagram? 

• Solid

• Liquid

• Gas

Multiple Choice

How are the particles moving in this state of matter?

• Moving around each other like marbles

• Vibrating

• Move quickly in straight lines

change of state

melting, boiling, condensing, and freezing

• Condensing - If a gas is cooled, it transfers energy to the surroundings, and turns into a liquid.

• Freezing - If the liquid is cooled, it transfers energy to the surroundings, and turns into a solid.

​cooling down - release energy

• Melting - When a solid is heated, it absorbs energy and it melts, turning into a liquid.

• Boiling - If the liquid is heated, it absorbs more energy and it boils, turning into a gas.

HEATING UP - absorb energy

change of state

Evaporating

Evaporating is when a liquid turns into a gas slowly, at temperatures that are below its boiling point. Puddles dry up because they evaporate – they don’t boil.

evaporating vs. boiling

Multiple Choice

What is done to chocolate to melt it?

• Heat it up

• Break it to pieces

• Cool it down

Multiple Choice

When melted chocolate turns back into a solid again, what happens to the thermal energy?

• It is absorbed from the surrounding

• It is transferred to the surrounding

Multiple Choice

What is the name of the process which occurs on the surface of the sea, when water moves into the atmosphere?

• evaporating

• boiling

• freezing

• condensing

Multiple Choice

If energy is removed from liquid water, what happens?

• It freezes

• It evaporates

• It turns into gas

• It boils

Multiple Choice

Which of the following is happening because of the cooling process?

• Melting

• Condensing

• Boiling

• Evaporating

atoms, elements, molecules, and compound

Atoms and elements

Atoms are the building blocks of all matter. Everything is made of atoms - even yourself.

Atoms are the smallest particle of an element, which are far too small to see. Even the most powerful microscopes cannot visualize a single atom!

An element is a pure substance that is made from only one type of atom. Everything in the universe contains the atoms of one or more elements. The atoms in one element are all the same as each other, but they are different from the atoms of any other element. There are 118 different elements. They are listed on the periodic table

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atoms, elements, molecules, and compound

molecules and compound

Molecules are made when two or more atoms chemically bond together. Atoms from different elements can combine. Water is made of molecules. Each water molecule is made from two hydrogen atoms chemically bonded to one oxygen atom. This means that the chemical formula of water is H₂O. Carbon dioxide is made of molecules of a carbon atom bonded to two oxygen atoms (CO₂).

Compound is created when atoms of two different elements combine. This term can only be used for something in a complete shape and visible to humans (it's like a group of molecules, but only those with different elements), for example table salt (NaCl)

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Multiple Choice

How many types of element can you spot?

• 3 elements: the black beads and the two red beads

• 2 elements: black beads and red beads

• Only one element

• Each connected beads are elements, so three

Multiple Choice

Atom, element, molecules, or compounds?

• Atoms

• Molecules

• Elements

Multiple Choice

What is the possible chemical formula for the molecules in the picture?

• CO2

• NaCl

• O2

• O3

Multiple Choice

This is the diagram of water molecules (H₂O). What is correct?

• There are three different types of element

• There is only one element

• The red beads represent H and the white beads represent O

• The red beads represent O and the white beads represent H

Multiple Choice

Atoms, elements, molecules, or compounds?

• Elements, because there is only one type

• Molecules, because it is made from atoms with same element

• Compounds, because two atoms joined together

Multiple Choice

This is the diagram of O2. Can we refer to this as an oxygen compound?

• Yes, because there are two atoms joined together even though they are from the same element

• No, because compounds can only be used for something made from two different element

Multiple Choice

How many atoms are there in total in a molecule of ethanol, CH₃CH₂OH?

• Two

• Three

• Eight

• Nine

Multiple Choice

How many elements are there in total in a molecule of ethanol, CH₃CH₂OH?

• Two

• Three

• Eight

• Nine

• The elements are arranged in order of increasing atomic number.

• The horizontal rows are called periods (we have 7 periods).

• The vertical columns are called groups (we have 8 groups*).

• Elements in the same group are similar to each other.

*Note that we skip the transition metal groups (from Sc to Zn) in the grouping

Modern Periodic Table

the periodic table

On the periodic table, metals are found on the left and in the middle, and non-metals are on the right. A zig-zag line divides them.

​Groups contain elements with similar chemical properties and physical properties. For example, the metals in group 1 are all reactive, whereas the elements in group 8 are all unreactive gases.

Metal and non-metal

the periodic table

Multiple Choice

What does the stepped zig-zag line beginning under boron (B) on the periodic table show? 

• Division between gases and solids

• Division between metals and non-metals

• Division between elements and compounds

• Division between transition metal and metal

Multiple Choice

Hydrogen is often shown separately on the periodic table. What type of element is it classified as?

• Metals

• Non-metals

• Neither

Multiple Choice

How many groups do we have in the periodic table?

• 7

• 8

Multiple Choice

The periodic table shows many rows in it. Why do we only have 8 groups?

• Because we skip the transition metal parts

• Because we skip the metal parts

• Because we skip the non-metal parts

Multiple Choice

How is the element arranged in the periodic table?

• By the increase of the mass number

• By the increase of the neutron number

• By the increase in the electron number

• By the increase in the atomic/proton number

We can find proton (+), neutron, and electron (-) in the atom.

In the center part of an atom, there is a nucleon which consists of protons and neutrons.

Electrons are orbiting in the shell around the nucleon

​

​Proton, electron, and neutron inside the atom

​atom structure

Atomic number = protons

The atomic number shows the number of protons in the atom. Remember that atoms of a given element have the same number of protons

An atom in a neutral state (no charge) contains equal numbers of protons and electrons. When they are unequal, the atom will be called an ion

​Proton, electron, and neutron inside the atom

​atom structure

In Sodium (Na), the atomic number is 11, hence a sodium atom has 11 protons in the nucleon

Mass number = protons + neutrons

The mass number shows the sum number of protons and neutrons in the atom.

Atoms of different elements usually have different mass numbers, but they can be the same. For example, the mass number of argon atoms and calcium atoms can both be 40

​Proton, electron, and neutron inside the atom

​atom structure

In Sodium (Na), the mass number is 23, while the protons are 11. So...

mass number = neutron + proton

neutron = mass number - proton

neutron = 23 - 11

neutron = 12

Multiple Choice

There sub-units that we can find inside an atom

• Protons, electron, ion

• Proton, electron, neutron

• Ion, proton, and neutron

• Ion, neutron, and electron

Multiple Choice

Correct statement about atom structure

• Electrons can be found in the nucleon

• Protons orbits/moving around the nucleon

• Neutron is the part of the nucleon

• Electrons and protons are part of the nucleon

Multiple Choice

Correct statements about protons

• They are positively charged

• They cannot be find in the nucleon

• They are negatively charged

• They are neutral

Multiple Choice

The numbers of protons and electrons on a neutral atom (not an ion) is equal

• True

• False

Multiple Choice

Ion will be formed when an atom has more protons than electrons

• True

• False

Fill in the Blank

How many electrons can be found in a neutral Lithium atom?

Fill in the Blank

How many neutrons can be found in a neutral Lithium atom?

Multiple Choice

The number of neutrons, protons, and electrons is the same

• True

• False