C1 Flashcards
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Properties of solids
Tightly packed
Strong bonds - Large forces between them
Highest density
Regular (Shape)
Vibrate
No space between them
Particles touching
It has low energy, and it only vibrates
It’s shape is
Fixed shape
Does not flow
Can not be compressed
Fixed volume
Fixed positions
Properties of liquids
Liquids have the following properties
Particles touching but can roll over each other
Weaker bonds - Weak forces between them
Lower density
Irregular / Random shape
Can move
No space
It has more energy than solid and moves around each other
It’s shape:
Takes the shape of bottom of container
Flows
Can not be compressed
Fixed volume
Properties of gas
Gases have the following properties
Separated / Far
Weakest / No bonds - Weak forces between them
Lowest Density
Random
Moving quickly
Particles not touching
Far apart
It has lots of energy so it has a lot of rapid movements
It’s shape:
No fixed volume
Fill the container
Can be compressed
Flow
No fixed shape
Solid to gas
Sublimation
Gas to solid
Deposition
What is a chemical change
Chemical change is any change that results in the formation of a new chemical substance. At the molecular level, it involved making or breaking bonds between atoms. This change is normally irreversible
What is a physical change
Physical change is any change that does not alter the substance’s chemical composition. A common example would be the change in states. Solid → Liquid etc. This change is reversible
Limitations of the particle model
Size
The size of particles vary in size a lot which is not properly shown in the particle model. For example a Helium atom is 62 pm, while a Lanthanum atom is 202pm. This is not shown properly in a particle model
Space between particles
The distance between atoms is not showing properly in the particle model. It is often shown as very close together in the model. However, in reality it is the opposite. The gap between helium atoms is 55x larger than the actual Helium atom.
Forces between atoms
There are forces between particles but this is not shown in the particle model
What is the centre of the atom called
The nucleus
What is the ring called in an atom
The shell
What are protons
Protons are found in the nucleus. They have a charge of +1 and they have a mass of 1
What are neatrons
Neutrons are found in the nucleus. They don’t have a charge (Neutral) and they have a mass of 1
What are electrons
Electrons are found in the shell. They have a charge of -1 and they have a mass of 0 or 1/2000
What is an atomic mass unit
An Atom Mass Unit (AMU) is 1/12th mass of 1 atom carbon-12
All the mass in the atom is in the nucleus. Atomic Mass = Proton + Neutron
Atoms are neutral so there has to be the same no. of protons and electrons as protons have +1 and electrons have -1 so they have to balance out
What does the image of a particle tell us in the periodic table
Atomic mass shows the amount of protons + neutrons added. This is the bigger of the two numbers.
Atomic number shows the no. of protons and electrons. This is the smaller of the two numbers
For Helium. Atomic number is 2 so there are 2 protons and 2 electrons. To find the neutrons. We know there are 2 protons. And the atomic mass is 4.
4 - 2 is 2. 2 neutrons