C1 Flashcards
Improve c1 knowledge
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
What are isotopes
Isotopes are atoms of an element with different numbers of neutrons.
Seen like this →35C, 37C
These are two different types of isotopes
Isotopes have the same number of protons and electrons.
Isotopes have a different number of neutrons
THe atomic number is the same
The mass number is different
Isotopes of the same element have similar chemical properties chemical properties
This means they react similarly to each other
They have different physical properties - Usually higher melting and boiling points
Usually higher densities
Isotopes sometimes may only be described by their mass number as this is the difference between them eg : Lithium-6,Lithium-7,Lithium-8
What are ions
Ions are atoms that has gained or lost electrons to become positively or negatively charged
Neutral atoms -
Positive Ions - Na+, Mg2+, Al3+
Negative Ions - F-, O2-
For example, If we take Na+. The charge is 1+, meaning that an electron is lost. If the charge was 1-, this would mean an electron has been gained
Note : The number of protons never change it is always the number of electrons that change so if we have more electrons we get negative charge but less electrons we get positive charge
What is the atomic mass
Atomic mass shows the amount of protons + neutrons added. This is the bigger of the two numbers.
What is the atomic number
Atomic number shows the no. of protons and electrons. This is the smaller of the two numbers
What is the only atom that doesnt want 8 electrons
Helium
Explain the Molymod kits
Carbon - black, oxygen - red, hydrogen - white, sulphur - yellow, nitrogen - blue, single covalent bond - a goofy grey thing
What did the ancient greeks discover about the atomic model
They used the term atom first. Democritus was the philospher
What did John Dalton discover about the atomic model
Discoveries made:
Atoms can not be broken down
Atoms of an element are identical to each other
Atoms of different elements are not identical
Elements have their own type of atom. Atoms are spheres
What did JJ thompson discover about the atomic model
Discoveries made:
Electrons
He was experimenting with Cathode ray tubes, and ending up finding the existence of electrons. A new model was proposed because of his new discovery of positive and negatively charged particles. He made the famous Plum Pudding model
What discoveries did Rutherford made about the atomic model
Discoveries made:
Gold leaf experiment
He found the idea of the positive small centre and a large electrically charged area around it
Atoms must be mainly empty space
There must be negatively charged particles around the area
There must be something dense and positively charged, meaning the nucleus
When he fired radioactive alpha particles at the gold leaf, he found that the particles would do one of 3 things
The particle went through
The particle went slightly off track
They bounced back
What did Bohr discover about the atomic model
Discoveries made:
The shell
He figured if the electrons were placed anywhere in the atom then eventually the electrons would crash into the nucleus. Therefore, discovering the existence of the shell
