Gcse Chemistry Paper 1 Atomic Structure And The Periodic Table Flashcards
What two particles in the nucleus of an atom made up of ?
- protons
* neutrons
Protons and neutrons have the same relative what?
- mass
What’s the relative mass for protons and neutrons
1
What is the relative mass for electrons
-very small
What is the relative charge for protons
+1
-positive
What is the relative charge for neutrons?
-0
What is the relative charge for electrons?
- 1
- negative
Most atoms have a radius of what?
-0.1nm
What happen when an atom has the same amount of protons and electrons?
- the amount of positive and negative electrons is equal
- so the relative charges balance out
- the atom is neutral (no overall charge)
Atoms have the ability to what?
-Lose or gain electrons
When an atom loses or gain an electron what do we call it?
- An Ion
What do you name an atom that has more electrons than protons?
Negative ions
-because there’s more negative electrons than positive protons
What do you name an atom that has more protons than electrons ?
- Positive ion
- because there’s more positive protons than negative electrons
What is an elemental symbol?
- is the one or two letter symbol that represents that element
- E.g oxygen is represented as O in the periodic table
What is atomic number?
- the atomic number is represented in the bottom left Corner of a nuclear symbol
- indicates number of protons present in the nucleus of an atom, which is also equal to the number of electrons in an unchanged atom
What is the mass number?
- Located on the top left side of the nuclear symbol
- this number tells us the total number of protons and neutrons in that atom
What do we do if we want to find out the number of neutrons an element has?
-mass number minus the atom number
What is an element?
-
-Elements are defined by the number of protons they possess
What happens when we change the number of neutrons in an element?
changing the number of neutrons form isotopes.
Define isotope
Isotopes are different forms of the same element,that have the same number of protons,but a different number of neutrons
relative atomic mass equation
Ar = sum of isotope mass x isotope abundance / 100
What is a molecule?
- 2 or more atoms ,held together by chemical bonds
- e.g oxygen are pairs of atoms that are bonded together so they’re classed as molecules
-molecules can contain diff elements e.g water oxygen atom is bonded to two atoms of hydrogen
What is a compound?
- 2 or more different Elements held together by chemical bonds
-e.g water because it contains two different elements which are:
• hydrogen and
•Oxygen
-another example is carbon dioxide it contains two different elements which are:
•oxygen
•Carbon
Why is the molecules like oxygen and chlorine not a compound?
-they only contain one type of element bonded together
What is a key feature of compounds?
- the elements involved are always found in the same proportions
- e.g water always has 2 hydrogen atoms an 1 oxygen atom
- allows us to write formulas for them using their chemical symbol and numbers of each atom e.g H2O
What is a mixture?
- two or more substances not chemically combined together
- lots of different substances that Haven’t reacted to each other
- so no chemical bonds between the individual substances
Why is it so easy to separate mixtures?
- because they’re not chemically combined together
- just physically mixed
Is carbon dioxide CO2 a molecule,compound or both?
- Both
- CO2 is a molecule because it contains 3 atoms chemically bonded together
- it is also a compound as it contains atoms of 2 elements (carbon and oxygen)
What is the first rule of balancing equations?
- Can’t change any of the little numbers
- We change the big numbers
What is the second rule of balancing equations?
- Keep to whole numbers
What is the type of mixture that’s separated in filtration
-separates insoluble solids from liquids e.g sand and water
What’s the process of filtration
- The insoluble solid (called residue) gets caught in the filter paper because the particles are too big to fit through the holes in the paper.
- The filtrate is the substance that comes through the filter paper
What type of mixture is separated in crystallisation/evaporation
A soluble solid and a liquid (e.g salt and water)
How do you separate a soluble solid and liquid?
- to separate a soluble solid from a (non- flammable) liquid we use evaporation. If we want to create hydrated salt crystals then do not evaporate all the water from the mixture
- the evaporating basin is wide and shallow, which gives the liquid a large surface area for quicker evaporation
What type of mixture is separated in simple distillation?
-soluble solid dissolved in a liquid (usually water) e.g salty water
What happens during simple distillation?
- The solution is heated, and pure water evaporates producing a vapour which rises through the neck of the round bottomed flask
- The vapour passes through the condenser, where it cools and condenses, turning into the pure liquid that is collected in a beaker
- After all the water is evaporated from the solution, only the solid solute will be left behind
What type of mixture is separated during simple distillation?
-separates soluble liquids with different boiling points e.g crude
