(Topic 1) Atomic Structure And Periodic Table (CGP Book) Flashcards
What is the radius of an atom?
0.1 nm
What do atoms contain?
Protons, neutrons, and electrons
Where is the nucleus located?
Middle of the atom
What does the nucleus contain?
Protons and neutrons
What is the radius of a nucleus?
1 x 10*14
What charge does the nucleus have?
A positive one
Where is the mass of an atom concentrated?
At the nucleus
What is the charge of a proton?
+1
What is the charge of a neutron?
0
What is the charge of an electron?
-1
What is the relative mass of a proton?
One
What is the relative mass of a neutron?
One
What is the relative mass of an electron?
Zero or very small
How do electrons move around?
They move around the nucleus in outer electron shells
What is the charge of an atom?
Neutral, this is because they have the same number of protons and electrons
What is an ion?
An atom or a group of atoms that has lost or gained electrons
What does the nuclear symbol of an atom tell you?
It’s atomic number and mass number
What does the atomic number show you?
How many protons there are?
What does the mass number show you?
The number of protons and neutrons in the atom
How do you find the number of neutrons in an atom?
Subtract the atomic number from the mass number
What is an element?
A substance made up of atoms that all have the same number protons in the nucleus
What is an isotope?
Elements that have the same number of protons but a different number of neutrons
What are compounds?
Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and are held together by chemical bonds
What happens in a compound which is formed from a metal and nonmetal?
The metal atoms lose electrons to form positive ions
The non-metal atoms gain electrons to form negative ions
The opposite charges of the ions means they are strongly attracted to each other. This is known as ionic bonding.
What happens in a compound that is formed from non-metals?
Molecules are formed
Each atom shares an electron with another atom
This is called covalent bonding
How can mixtures be separated?
Filtration, crystallisation, simple distillation and fractional distillation
What is crude oil?
A mixture of different length hydrocarbon molecules
Process of paper chromatography?
Draw line near bottom of a sheet of filter paper
Add spot of ink to line and place sheet in a beaker of solvent
Make sure ink is not touching solvent
Solvent seeps up paper carrying ink with it
Each different diet in ink will move paper at a different rate so will separate forming a separate spot
If any dyes are insoluble, they will stay on the baseline
When solvent has reached top of paper, take it out and leave to dry resulting in a chromatogram
When can filtration be used?
If your product is an insoluble solid that needs to be separated from a liquid reaction mixture
What does filtration do?
Separate insoluble solids from liquids
What does soluble mean?
A solid that can be dissolved
What are two methods for separating a soluble salt from a solution?
Evaporation and crystallisation
Process of evaporation?
Pour solution into evaporating dish
Slowly heat solution, solvent will evaporate and solution will get more concentrated. Eventually crystals will start to form
Keep heating evaporating dish until dry crystals are left
Process of crystallisation?
Call solution into evaporating dish and gently heat solution, some of solvent will evaporate and solution will get more concentrated
Once some of solvent has evaporated remove dish from heat and leave solution to cool
Salt should start to form crystals as it becomes insoluble in cold highly concentrated solution
Filter crystals out of solution and leave them in a warm place to dry
What is simple distillation used for?
To separate out solutions
Process of simple distillation?
Solution is heated, part of solution that has lowest boiling point evaporates first
Vapour is then cooled, condenses and is collected
Rest of solution is left in flask
What is fractional distillation used for?
To separate a mixture of liquids
Process of fractional distillation?
Put mixture in flask and stick a fractionating column on top then heat it
Different liquids have different boiling points so will evaporate at different temperatures
Liquid with lowest boiling point evaporates first
Liquids with higher boiling points further up the fraction it in column before running down to the flask
When and what did John Dalton say about the atomic structure?
Start of 19th century described atoms as solid spheres and said that different spheres made up different elements
When and what did JJ Thompson say about the atomic structure?
1897, he concluded from his experiments that atoms were not solid spheres
Measurements of charge and mass showed that an atom must contain even smaller negatively charge particles
He called his theory the plum pudding model
What did the plum pudding model show?
The atom is a ball of positive charge with electrons stuck in it
When and what did Ernest Rutherford say about the atomic structure?
In 1909, conducted Alpha particle scattering experiments
Fired positively charged alpha particles at an extremely thin sheet of gold
Most of particles went straight through some of deflected, and a small number with deflected backwards, this disproved the plum pudding model
What was Rutherford’s new model of the atomic structure called?
The nuclear model
Demonstrate a tiny positively charged nucleus at centre, where most of mass is concentrated
A cloud of negative electrons surround the nucleus most of atom is empty space
What did Niels Bohr say about the atomic structure?
Suggested all electrons were contained in shells which orbit the nucleus
What did James Chadwick state about the atomic structure?
Discovered neutral particles in nucleus known as neutrons
How were elements arranged in the early 1800s and why?
By atomic weight
Scientists had no idea of atomic structure or of protons, neutrons of electrons
What was wrong with early periodic tables?
They were incomplete and some elements placed in wrong group
When and what did Dimitri Mendeleev state about the periodic table?
Took 50 non-elements and arrange them into his table of elements and left various gaps
Elements mainly in order of atomic weight but also by their properties
When elements were found, they fitted the gaps he left
How is the modern periodic table organised?
Elements laid out in order of increasing atomic number, this means there are repeating patterns in properties of elements
Vertical column are called groups and Represent elements with similar properties
Group tells you how many electrons in outer shell
Rows are called periods
What are metals?
Elements which can form positive ions when they react
How do elements gain a full outer shell?
They react and either lose, gain or share electrons
How do metals bond?
Metallic bonding
Properties of metals?
They are strong but malleable
Great at conducting heat and electricity
Have high boiling and melting points
Properties of nonmetals?
Tend to be dull looking
More brittle
Aren’t always solids at room temperature
Don’t generally conduct electricity
Often have a lower density
Properties of transition metals?
Good conductors of heat and electricity
Very dense, strong and shiny
Can have more than one ion
Often coloured
Often make good catalysts
Where are the transition metals found?
Groups two and three
What are group one elements known as?
The alkali metals
Properties of alkali metals?
Reactive
Soft
One electron in outer shell
Low density
What happens as you go down group one?
Increasing reactivity
Lower melting and boiling points
Higher relative atomic mass
What happens when alkali metals react with water?
React vigourously to produce hydrogen and metal hydroxides
What is a metal hydroxide?
Compounds that dissolve in water to produce alkaline solutions
How do group one elements react with chlorine?
React vigourously when heated in chlorine gas to form white metal chloride salts
How do group one elements react with oxygen?
React with oxygen to form a metal oxide
What are group 7 elements known as?
The halogens
What colour gas is fluorine?
Yellow
What colour gas is chlorine?
Green
What colour gas is bromine?
Red/brown
What colour is iodine?
A dark grey crystalline solid
Purple vapour
What happens as you go down group 7?
Less reactive as it is harder to gain an extra electron because the outer shell is further from the nucleus
Higher melting and boiling points
Higher relative atomic masses
How do halogen atoms share electrons with other non metals?
Covalent bonding
How do halogens bond with metal?
Ionic bonding
What are group 0 elements known as?
Noble gases
Properties of noble gases?
Stable as have full outer shell
Colourless gases
Non-flammable
What happens as you go down the noble gases?
Boiling points increase because of an increase in number of electrons in each atom leading to greater intermolecular forces
Relative atomic mass increases
