Atomic Structure And Bonding Flashcards
Which subatomic particles are located in the nucleus
Protons, neutrons
Which subatomic particle are in the shells
Electrons
What is an element
A substance that is made of only one sort of atom
How many elements are there
118
What does atomic mass show
The total number of protons and neutrons in its nucleus and is represented by symbol A as it is on top
What does atomic number show
Number of protons and electrons the symbol for this number is Z as it is at the bottom
What does period number show
(Goes across ) Number of shells
What do groups show on the periodic table
(Vertical columns) same number of valence electrons (ones in the outer shell)
Group one
Alkali metals
Group 2
Alkaline earth metals
Group 7
Halogens
Group 0
Noble gasses
What is a compound
A pure substance made up of 2 or more elements chemically combined which cannot be separated by physical means
What is a mixture
Consists of 2 or more different substances not chemically joined together
Ionic bonding
Ionic bonding is the electrostatic attraction between positively charged ions and negatively charged ions formed when atoms transfer electrons from one to another.
Covalent bonding
A covalent bond is between non metals it is a chemical bond that involves the sharing of electrons to form electron pairs between atoms.
Metallic bonding
The metallic bond is the force of attraction between these free-moving (delocalised) electrons and positive metal ions
What is an ion
Electrically charged particle formed when an atom or molecule gains or loses an electron (s)
What do chemical equations show
The reactants ( those on the left side of the arrow the substance that takes part in and undergoes change during a reaction) and the products (the substances produced at the end of a reaction)
What does the arrow show in chemical equations
The conversion of reactants into products
What is written above the arrow
Reaction conditions or the name of a catalyst ( a substance added to make a reaction go faster)
What is a symbol equation
A symbol equation uses formulae of the reactants and products to show what happens in a chemical reaction and must be balanced to give the correct ratio of reactants and products
Why must equations be balanced
Atoms cannot be created or destroyed so if they exist in the reactants then they must be in the products
How are new substances made
During chemical reactions however the same atoms are always present before and after the reaction they have just joined up in different ways
What is the law of conservation of mass
no matter is lost or gained during a chemical reaction, mass is always conserved, therefore the total mass of the reactants is equal to the total mass of the products, which is why all chemical equations must be balanced.
What do all measures of separating mixtures rely on
There being a difference in a physical property such as the boiling point or solubility between the substances being separated
Charge and relative mass of a proton
Charge +1 mass 1
Charge and relative mass of a neutron
Charge 0 relative mass 1
What is the charge and relative mass of an electron
Charge -1 relative mass 0
What is the relative charge of an atom
Neutral as even though they contain charged subatomic particles the charges cancel each other out
How to remember which is mass and which is atomic number
Think MASS = MASSIVE as mass number is the bigger of the 2 numbers so the smaller one must be the atomic number
How to calculate number of neutrons
Mass number - atomic number
What is the outermost shell of an electron called
Valence shell
What are negative and positive ions also called
Negative - anions
positive - cations
What charge are metal ions
They loose electrons and become positive
What charge are non metal ion s
They gain an electrons and become negative
What is the structure of ionic compounds
It has a giant lattice structure with strong electrostatic forces of attraction as a result of this ionic compounds have high melting and boiling points
How are molecules formed
When 2 or more atoms are covalently joined together
What is the properties of metals
Metals are shiny, conductive materials with malleable and ductile properties, they conduct heat and electricity due to the sea of delocalised electrons which can carry charge through the metal lattice structure
Describe the arrangement of solids
1)Strong forces of attraction between particles, particles are packed very closely together in a fixed and regular pattern
2)Atoms vibrate in a fixed position but can’t change position or move
3)Solids have a fixed volume and shape, and a relatively high density
4) Solid particles have only a small amount of energy
Define melting, boiling, freezing, evaporation condensation, sublimation and deposition
Melting- solid to liquid
Boiling- liquid to gas
Freezing- liquid to solid
Evaporation- liquid to a gas
Condensation- gas to liquid
Sublimation- solid to gas
Deposition- gas to solid
Describe the properties of liquids
1) Liquids have a fixed volume but take the shape of their container because their particles can flow past each other
2) they are incompressible due to minimal space between particles
3) liquid particles are closely packed together and can move past eachother
Describe the properties of gases
1) Gases are compressible due to the large spaces between particles allowing them to be pushed closer together.
2)They expand to fill any container as their particles move freely.
3)Gasses have low density because the particles are widely spaced
4)The particles move rapidly and randomly in all directions
Aqueous definition
A substance which is dissolved in water in other words a solution
State symbol of solid liquid gas an aqueous
s l g and aq
What is a molecule
A particle that consists of two or more atoms chemically bonded together
What is an alloy
a mixture of two or more elements at least one of which is a metal
What is a simple covalent structure
small molecules that are formed by covalent bonds between non-metal atoms.
These molecules are held together by strong covalent bonds internally, while the forces between the molecules (intermolecular forces) are weak, resulting in low melting and boiling points.
What are the properties of giant covalent substances
High melting and boiling points: Due to the strong covalent bonds between atoms throughout the structure, it requires a significant amount of energy to break these bonds, resulting in high melting and boiling points.
Hard and brittle: These structures are generally hard and brittle because the strong covalent bonds make it difficult to deform the structure. When a force is applied, the structure tends to fracture rather than bend or deform.
Poor electrical conductivity - Most giant covalent structures are poor conductors of electricity because they do not have free-moving electrons. However, some exceptions exist, like graphite, which has a layered structure with delocalized electrons that can conduct electricity along the layers.
Insoluble in water-due to their strong covalent bonds
Examples of giant covalent structures
Diamond graphite and silicon dioxide
describe the shape and structure of diamond
Diamond has a tetrahedral structure where each carbon atom forms 4 strong covalent bonds with other carbon atoms creating a 3D lasttice
Describe the shape and structure of graphite
Graphite has a layered structure where each carbon atom forms 3 covalent bonds with other carbon atoms in hexagonal layers with one free electron per atom allowing for weak forces between atoms
Describe the hardness conductivity and solubility for diamond
Hardness- the strong covalent bonds throughout the lattice make diamond extremely hard
Conductivity - no free electrons to carry current meaning it doesn’t conduct electricity
Solubility - insoluble because of the strong covalent bonds
Describe the hardness conductivity and solubility of graphite
Hardness- the week intermolecular forces between layers allowing them to slide over eachother make graphite soft
Conductivity - the delocalised electrons between layers allow graphite to conduct electricity
Solubility - insoluble because of the strong covalent bonds within the layers
Describe the melting points of diamond and graphite
Very high melting point because they contain strong covalent bonds
Why does alloying a metal make the metal harder
Because the regular layers in a pure metal are distorted by atoms of different sizes in an alloy, so the layers no longer slide over eachother making them harder
Explain why aluminium (group 3) has a higher melting point than sodium ( group 1 )
Because aluminium atoms form al3+ ions which have a stronger attraction to delocalised electrons compared to sodiums Na+ ions.
Aluminium also contributes 3 delocalised electrons per atom strengthening the metallic bond, whereas sodium only contributes 1
The smaller size of aluminium ions further increases the strength of the electrostatic attraction making metallic bonding in aluminium much stronger requiring more energy to break resulting in a higher melting point
What is electrostatic bonding
The force of attraction between oppositely charged particles, in ionic compounds it it the force that holds positively charged ions and negatively charged ions together
What is graphene and its properties
Graphene is a single layer of graphite and so is one atom thick
Its properties, such as its excellent electrical conductivity, will help create new developments in the electronics industry in the future
Describe the shape of buckminster fullerene and state its molecular formula
a ball shaped molecule made from 60 carbon atoms forming hexagonal and pentagonal bonds around the edge of a sphere
Molecular formulary C60
Describe how fullerenes can be used in medicine
Hollow- so you can put medicines inside it designed to target specific cells
Explain why fullerenes make good catalysts
They have a huge surface area compared to volume ratio which gives them potential uses in applications that rely on surface area like catalysts
Explain where the name buckminster fullerene comes from
Named after the eccentric inventor buckminster fuller
Are giant covalent structures soluble
No they are insolable in water
What is the cause for low melting and boiling points
Weak intermolecular forces between molecules
Why is buckminster fullerene lubricant
- Because its molecules are shaped like hollow spheres
- These spherical molecules can roll over each other
- Reducing friction between surfaces
- Making it an effective lubricant
Why is silicone dioxide good for a welding blanket
Silicone dioxide is a giant covalent structure, meaning that it has very strong covalent bonds which require a-lot of energy to break
Why is nitinol good for dental braces
- Shape memory property meaning it returns to original shape after being deformed
Why are metals good at conducting electricity
Metals are good conductors of electricity because there is a sea of delocalized electrons that can move freely and carry electric charge throughout the structure
