Atomic Structure and the Periodic Table Flashcards
Structure of the Nucleus
- In the centre of the atom
- Contains protons and neutrons
- Positively charged because of protons
- Has a radius of 1x10-14
Electrons
- Orbit the nucleus in shells
- Negatively charged
- Volume of orbit determines size of the atom
- Have a very small mass
Proton Relative Mass and Charge
- Relative Mass: 1
- Charge: +1
Neutron Relative Mass and Charge
- Relative Mass: 1
- Charge: 0
Electron Relative Mass and Charge
- Relative Mass: Very Small
- Charge: -1
Why is the overall charge of an atom 0?
There are an equal amount of protons and electrons in an atom so the charge cancels out
Relative Atomic Mass Formula
Total mass of atoms/Total number of atoms
Top and Bottom Numbers on Nuclear Symbol
- Top: Mass Number
- Bottom: Atomic Number/Proton Number
Number of Neutrons Calculation
Mass Number - Atomic Number
Solute
A substance that is being dissolved in a solvent
Solvent
The liquid that the solute dissolves in
Solution
A mixture made when a solute dissolves into a solvent.
Simple Distillation
Used to separate a liquid from a solution
Simple Distillation Method
- Heat flask using a bunsen burner so the liquid that is being separated evaporates
- The vapour of said liquid rises to the top of the flask and passes through the condenser
- The cold water in the condenser causes the vapour to cool and condense
- The liquid runs down the pipe and is collected in a beaker
Fractional Distillation
Used to separate mixtures of liquids with different boiling points
Fractional Distillation Method
- Heat flask using a bunsen burner so the liquid with the lowest boiling point condenses first
- The vapour rises through a column that is hotter at the bottom and cooler at the top
- It rises up the fractioning column, passes through the condenser and condenses
- Collect the condensed liquid
- You are left with the other liquid in the flask
Newlands Periodic Table
- Ordered by atomic weight and maintained this order
- Every 8 elements had similar properties
- Didn’t work as it forced Newlands to group elements that didn’t have similar chemical properties
- Wasn’t accepted by other scientists
Mendeleev’s Periodic Table (The table we use to this day)
- Ordered elements by atomic weight
- Left gaps for undiscovered elements
- Swapped the order of some elements based on if their properties matched better elsewhere
- Elements in groups had similar chemical properties
- Accepted by other scientists when newly discovered elements were found to fit Mendeleev’s system
Why do metals form positive ions?
- They don’t have many electrons in their outer shells
- The outer electron can be lost more easily as it would require less energy
Why does reactivity increase down metal groups?
- Elements further down the table have more shells
- The outer shell would be further from the nucleus so the attraction between the 2 is weaker
- The electron is more easily lost
Non Metals
Form either no ions or negative ions
Metal Properties
- High melting and boiling points so are solids at room temperature
- Good conductors of heat and electricity
- Lustrous (shiny)
- Malleable
- Sonorous
- Have high densities
Non Metal Properties
- Poor conductors of heat and electricity
- Appear dull
- Weak and brittle
- Low melting and boiling points so liquids and gases at room temperature
- Not sonorous
- Low densities
Transition Metals
- Can form more than 1 type of ion
- Form coloured ions
- Melting points and densities are higher than group 1 metals
- Stronger and harder than group 1 metals
- Shiny when freshly cut
Group 1 Metal Properties
- Reactive, soft metals
- Alkali metals
- Low density
- More reactive than transition metals
- React vigorously with water, oxygen and group 7 elements
Group 1 Trends
- Reactivity increases down the group
- Melting and boiling point decrease down the group
- Relative atomic mass increases down the group
Group 1 Reactions
- Group 1 + water –> Metal Hydroxide + Hydrogen
- Group 1 + Chloride –> Metal Chloride + Salt
- Group 1 + Oxygen –> Metal Oxide
Group 7 Properties
- Non metals
- All halogens are diatomic molecules
- At room temperature, fluorine is a pale yellow gas, chlorine is a pale green gas, bromine is an orange liquid and iodine is a grey solid
Group 7 Trends
- Relative atomic mass increases down the group
- Melting and boiling points increase down the group
- Reactivity decreases down the group
Group 0
- Have full outer shells so they are unreactive
- Exist as single atoms
- Non-flammable
- Boiling point increases down the group
What is the limitation of a dot and cross diagram?
It doesn’t show how the atoms are arranged in space
What are the limitations of a ball and stick diagram?
- Not to scale
- Doesn’t give information about the forces pf attraction of the movement of electrons to form the ions
