C1 & C2- Atomic structure and the periodic table Flashcards
What is an element (3)
.They are simple substances that cannot be split into smaller ones by chemical reaction
. They are made up of atoms
. Each element is made of the SAME kind of atom
What are the two elements in carbon
Carbon, Oxygen
What is an atom
Is the smallest part of an element that can exist
. Made up of 3 subatomic substances ; protons(+) neutrons(o) electrons (-)
Properties of a proton (relative charge and relative mass)
Relative charge +1
Relative mass 1
Relative charge and relative mass for neutrons
Relative charge 0
Relative mass 1
Relative charge & mass for an electron
Relative charge -1
Relative mass 1/2000
Radius of an atom
O.1nm (1x10to the power of -10m)
Radius of a nucleus
1/10000 that of the atom
What is in the atomic structure (3)
. Nucleus
. Protons, neutrons, electrons
. Rings or electric shells on the outside
What is a molecule
A small group of atoms that are covalently bonded
Monatomic elements (3)
. Consist of single atoms
. All noble gases
. Very stable and unreactive
Diatomic elements
. Consist of two atoms covalently bonded
.
Polyatomic elements
. Consist of multiple covalently bonded atoms
What is the atomic number
- Number of PROTONS an element contains in its nucleas
* Is the bottom number
What is the mass number
The number of PROTONS + NEUTRONS an element contains in its nucleas
Is the top number
What is an isotope
Are elements with a different number of neutrons but the same number of protons
Two main types of atomic models
Plum-pudding (jj thompson) Nuclear model (Ernest Rutherford)
JJ Thompson
1) What did he discover
2) what year
3) how was his idea different to Daltons
4) what was the name of his model
1) the elctron
2) 1897
3) Daltons theory that atoms cannot be broken to smaller parts
4) plum pudding
John Dalton
1) what were his conclusions
2) what time were these made
3) whose idea did he revive
4) did he believe atoms could be broken to smaller parts
1) element were made of one type of atom
2) 1800s
3) greek philosophers
4) yes
Mandeleev breakthrough
In 1869 solved the problem of the periodic table. Placed atoms in a table according to their weights. Left gaps for undiscovered elements. Years later new elements were discovered closely matching Mandeleev’s predictions and there were few doughters of his theory. However until 20th century scientists found out mire about the structure if an atom
Properties of Group 1 (alkali metals)
.Their reactivity increases as you go down the group
. React with oxygen to produce a base
. React with water to produce an alkali and hydrogen gas
Common observations for lithuim, sodium, potassium
Easy to cut
Stored under oil
React quickly with air
Where, generally are the metals located on a periodic table
Bottom and to the left
Where, generally are the nonmetals located on a periodic table
At the far right and top
Properties of metals (4)
. Strong
. Malleable
. Great heat and electricity conductors
. High boiling and melting points
Properties of non metals (5)
. Tend to be dull looking . More brittle . Aren't always solids(at room temperature) . Dont generally conduct electricity . Often have a lower density
Properties of halogen (3)
.Low melting and boiling points which increase as you go down
. Poor conductor of heat and electricity
. Exist as diatomic molecules
What is an ion
An ion is a charged atom that can be negative or positive
Do atoms that lose electrons from positive or negative ions
Positive
Do atoms that gain electrons from positive or negative ions
Negative
How are ionic compounds held together
They are held together by very strong forces
Properties of giant ionic structures (3)
. Hold together through very electrostatic attraction
. Have high melting and boiling points (because of there very strong bonds)
.solid
What happens in ionic bonding
Atoms either lose or gain electrons forming charged particles called ions
How many electrons do groups 1,2,3 lose or gain to form positive or negative ions
1) lose 1 electron to form positive ion
2) lose 2 electrons to form positive ions
3) lose 3 electrons to form positive ions
How many electrons do groups 6,7 lose or gain to form positive or negative ions
6) gain 2 electrons to form negative ions
7) gain 1 electron to form positive ions
How are ionic compounds usually found
When metals react with non metals
How are compounds formed
When elements react, atoms combine with other atoms
What is a compound
A compound is 2 or more elements chemically bonded together
One method of separating substances in a mixture
Chromatography
Examples of compounds
. Carbon dioxide (CO2) . Ammonia (NH3) . Water (H2O) . Hydrochloric acid (HCL) . Sulfuric acid (H2SO4)
What is the trend for group 1 elements
They get more reactive as you go down
What is the trend for group 7 elements
Get less reactive as you go down
Why does the trend in group 1 elements happen
. The atoms get larger when you go down therefore the the single electron in the outermost shell is attracted less strongly to the positive nucleus
. The electrostatic attraction gets weaker as the distance increases
. Size of the positive nuclear charge gets larger as you go down as there is more protons
. The greater the distance and shielding effect of inner electrons outweigh the increasing nuclear charge
Features of a mixture
. No chemical bond between the parts
. Parts can be either elements or compounds
. Chemical properties of a substance aren’t affected by it being part of a mixture
What is a mixture
Is something made from molecules of elements and compounds that are simply mixed together
What is the law of conservation of mass
The total mass of the products formed in a reaction is equal to the mass of the reactants
How are elements arranged in groups and periods in the periodic table
. They are ordered of increasing atomic number
. Elements with similar properties are in the same group of elements
Why has the ordering of elements changed over time
Scientist keep discovering new elements which can be filled in to the periodic table
How is electronic structure linked to the periodic table
. The number of occupied shells is the same as the period number (row in the table)
. The number of electrons in the outer shell is the same as the group number (column in the table)
How does the electronic structure of metals affect their reactivity
. Metals to the left don’t have many electrons to remove and metals towards towards the bottom have outer electrons which are a long way from the nucleus so feel a weaker attraction
. This then means that not much energy is needed to remove the electrons so its feasible for the elements to react to form positive ions with a full outer shell
How does the electronic structure of non metals metals affect their reactivity
. Forming positive ions is much more difficult this is because they have lots of electrons to remove to get a full outer shell (as they are to the right of the periodic table)
. Towards the top the outer electrons are close to the nucleus so feel a strong attraction so its far more feasible for them to either share or gain electrons to get a full outer shell
What are noble gases and why are they unreactive
. Noble gases are group 0 elements which are very unreactive
. They are unreactive because their electronic structure is very stable therefore don’t need to give up or gain electrons to become more stable
Why do elements in group 1 react similarly
They all have one electron in their outer shell therefore it makes them very reactive and have them similar properties
Why do the first 3 elements in group 1 float
. They react vigorously in water producing hydrogen in the form of bubbles and since its a very light gas stick to the surface of the metal
Equation that shows that hydrogen and metal hydroxides are made when group1 elements react with water
Sodium(2nNa) + Water (2H20) -> Sodium hydroxide (2NaOH) + hydrogen (H2)
How are group 1 metals stored and safety precautions used when dealing with them
. Alkali metals need to be stored under oil to prevent them reacting with the oxygen and water vapour in the air
. Wear goggles and gloves as they are corrosive
Trends of halogens
. It gets less reactive as you go down as its harder to gain an extra electron, because the outer shell’s further from the nucleus
. As you go down the halogens have higher melting and boiling points
. As you go down higher relative atomic masses
Why do elements in group 7 react similarly
Because they all have seven electrons in their outer shell
How do group 7 non metals form ions with a -1 charge when they react with metals
Non metal atoms gain electrons when they react with metals therefore when a halogen atom reacts it gains one electron into their outer shell to forma singly negative charged ion
How does a halogen displacement reaction occur
Between a more reactive halogen and the salt of a less reactive one and the displacement will happen depending in the trend of reactivity
What are covalent bonds? (2)
- Are bonds formed when atoms share pairs of electrons
* These bonds between atoms are very strong
Covalently bonded substances (2)
- Some have very large molecules e.g polymers
* Some have giant covalent structures e.g diamond and silicon dioxide
What is metallic bonding?
Is when atoms share delocalised electrons (metals)
What is the relationship between group numbers and number of electrons in the outer shell? (2)
- Group numbers tells you how many electrons there are in the outer shell
- e,g Group 1 have one electron and Group 7 have 7
Diamond (4)
- Each carbon atom forms 4 covalent bonds
- Very rigid giant covalent structure
- Requires lots of energy for bonds to be broken - so have very high melting points
Graphite (2)
- Each carbon atom forms 3 covalent bonds - creating 2d layers of hexagons
- Each carbon atom has a delocalised electron
How are metals good conductors of heat and electrical energy
The delocalised electrons carry electric current and thermal heat through the whole structure allowing them to be good conductors of heat and electricity
Fullerenes (2)
- Buckminister fulerene - have medium electrical conductivity due to some non-bonding electrons
- Fullerenes can be used for drug delivery systems in the body, in lubricants and as catalysts
