Structure And Bonding Flashcards
What is the charge on an electron
-
What is the change on a neutron
0 charge
What is the mass of: protons neutrons and electrons?
Protons - 1
Neutrons - 1
Electrons - 1/2000 (approx)
How are elements ordered in the periodic table?
They are arranged in atomic number
What is atomic number?
Number of protons
What is atomic mass
Number of protons and neutrons
Is the atomic number or atomic mass on top on the periodic table?
The atomic mass is on top
Why are atoms electrically neutral?
Because they have the same number of positive and negative charges ( protons and electrons)
What is the attraction of positive and negative ions?
The electrostatic force of attraction
What is the charge on a proton?
Positive
What is the relationship between the number of electrons in the highest energy level and the group number?
The number of electrons in the outer shell belong to the same group on the periodic table
Why do atoms react and bond?
In order to gain a full outer shell to become stable
How are the ions held together in eg solid magnesium oxide?
They are held together by the electrostatic force of attraction between positive and negative ions
Property of diamond?
Hardness
What is an element?
A substance which contains one type of atom
What is the difference between a mixture and a compound?2
Mixtures contain more than one element
Compounds are chemically bonded mixtures aren’t
Why are metals malleable and ductile?
Because metals are arranged in layers
So the layers of ions can slide over each other
Why do metals conduct electricity?
Because they are held together in an see of delocalised electrons but the electrons are able to move because the electrons are free to carry charge
Why do metals have high melting/boiling points?
- strong electrostatic is between positive ions and electrons that take a lot of energy to break
What is the arrangement of metal atoms?
Closely packed in layers
Physical properties of metals?6
- good conductor of heat and charge
- shiny
- generally hard (and solid)
- malleable
- alloys
- generally grey
Two elements with giant covalent structures?
Diamond and carbon
What state are ionic substances at at room temperature?
Solid
Why do ionic substances have high boiling points?3
Because they form strong bonds
Because of the electrostatic force of attraction oppositely charged ions
so a lot of energy is required to break them
Do ionic substances have low melting points?
No they are high
Why will ionic compounds conduct electricity when molten or in solution?
Because their ions can move freely and thus carry charge through the liquid
At room temperature what are simple molecules?
They are liquids or gases
Why don’t simple molecules conduct electricity? 3
There is overall charge on a simple molecule
so they can’t carry electrical charge
& no free electrons
Why do substances made up of simple molecules have low boiling points?3
- between molecules
- there are weak intermolecular forces
- not much energy is required to break them and boil the substance
Describe an ionic lattice? 3
- regular arrangement ( in rows)
- held together by an electrostatic force of attraction
- between oppositively charged ions
In a simple molecule what is strong and what is weak?2
The covalent bonds are strong
The forces between molecules are weak
Examples of simple molecules? 4
CO
HCl
CO2
H2
Physical properties of diamond?4
- very hard
- very high boiling/melting point
- insoluble in water
Physical properties of graphite?3
Soft
Slippery
Conducts electricity
Why is graphite slippery?3
There are weak intermolecular forces between the layers so
They can then slide over eachother
Making graphite soft and slippery
Why is diamond hard?4
The atoms in diamond form a giant structure
They form strong covalent bonds
They form 4 bonds
So lots of energy is required to break the bonds
Why can graphite conduct electricity?
- it only makes three bonds to Carbon
- this leaves a delocalised electron ( because it is arranged in layers)
- can travel between the layers carrying charge
Why can’t diamond conduct electricity? 2
- Diamond does not have delocalised (free) electrons
- because they are all used in bonding
How many bonds to carbon does diamond/graphite make?
4 and 3
Examples of giant covalent structures?3
Silicon dioxide
Diamond
Graphite
Describe the bonding in metals?
The bonding is strong because of the electrostatic force of attraction between ions and electrons
What is a giant covalent structure?
A huge 3D network of covalently bonded atoms eg diamond or graphing
What is a covalent bond?
A shared pair of electrons
How is a covalent bond formed?3
- When an atom wants to become stable
- it can covalently bond to share electrons between the atoms
- to form a full outer shell
explain the bonding in giant covalent structures?4
- Lots of bonds
- very strong bonds
- covalent bonds
- held together in regular giant lattices
Why is graphite softer than diamond?4
- graphite has weak intermolecular forces
- graphite is in layers that can slide over eachother
- in diamond each atom had no free electrons as in bonded to 4
- so no carbon atoms can slide over eachother
What are nano particles?
Particles of size 1-100 nm
Why does carbon dioxide have a low boiling point?3
- carbon dioxide is a simple molecule
- there are weak intermolecular forces between the molecules
- so not much energy is needed to break them
How does a positively charged hydrogen ion change into a hydrogen atom?
Gains one electron
Why is silicon dioxide a suitable material for lining furnaces?
- high melting point
- lot of energy needed to break its bonds
- because it has strong bonds
- because it is a giant structure
Describe the structure of a metal?
Sea of delocalised electrons
Positively charged metal ions
Describe the structure and bonding of a metal?
Positive ions
Sea of delocalised electrons
That carry charge
Giant lattice
Why use a certain metal for dental braces?
Shape memory alloy
How does an ion form?
When atoms form chemical bonds by transferring electrons
Alkali metals react with non metals to form what?
Ionic compounds
In which the metal ions has a single positive charge
What does a compound contain?
Two or more elements which are chemically combined
What is a compound?
Substances in which 2 or more elements are chemical combined
Why do ionic compounds have high melting and boiling points?
Because lots of energy is required to break the many strong bonds
What do metals consist of?
Giant structure of atoms in a regular patterns
Delocalised electrons held in place by positive ions (electrostatic force of attraction)
Describe force in ionic lattices?
The force exerted by an ion on other ions in the lattice acts equally in all directions
Why are ionic structures held together so strongly?
Force exerted by an ion on other ions acts equally in all directions
