Atomic Structure And The Periodic Table (C1) Flashcards
What is the radius of an atom?
0.1nm
1X10^-10m
What is the Nucleus?
The Nucleus is the centre of an atom. The Nucleus... - has protons - has neutrons - has an overall positive charge - contains (most) of an atom's mass - has a radius of 1X10^-14m (1/10,000th of an atom) (See Figure 1, Page 1)
What are Electrons?
Electrons are negatively charged sub atomic particles.
Electrons…
- move around the nucleus in orbiting electron shells
- are negatively charged
- are extremely small but cover a lot of space
- volume of their orbits are defined by the size of the atom
- have virtually no mass
What are the 3 subatomic particles and their relative charges and mass.
Particle - Relative Mass - Relative Charge
Proton = 1 = +1
Neutron = 1 = 0
Electron = (>0) = -1
What is the charge of an atom?
Neutral as they have equal protons (+1) as electrons (-1)
What is an ion?
An atom which has gained or lost electrons (often to obtain a full outer shell)
What is the charge of an ion?
It is the amount of protons - the amount if electrons on the ion.
If it has 2 more electrons than the original atom, it has a charge of 2-
If it has 3 less electrons than the original atom, it has a charge of 3+
What is the Mass Number?
Mass of the atom - protons + neutrons
See Figure 2, Page 1
What is the Atomic Number?
Number of protons in an atom
See Figure 2, Page 1
What defines what element an atom is?
Atomic Number defines the element of an atom. This never changes.
What is an element symbol and what is it good for?
Every element has their own unique symbol. This consists of 1 or 2 letters usually derived from Latin.
The first letter is always capital (and if there is a second it is always lower case)
These symbols are shorthand and universal.
(See Figure 2, Page 1)
Roughly how many different elements exist?
Around 100
What is an isotope?
An isotope is an atom of a specific element that has the ‘wrong’ number of neutrons.
(For example if a carbon atom (that typically has 6 protons, 6 neutrons and 6 electron) has instead 6 protons 7 neutrons and 6 electrons. It is still the same element as the number of protons hasn’t changed and it is still a neutral atom as there are still equal protons and electrons.)
Why do some periodic tables have mass numbers with decimal places?
Isotopes occur naturally and we can calculate their abundance. This is why on more specific periodic tables may have decimal places on their mass numbers.
How do you calculate the relative atomic mass of an isotope?
Relative Atomic Mass (Ar) = sum of (isotope abundance X isotope mass number / sum of abundances of all the isotopes
What is a Compound?
When two or more particles react and chemically join together, they form compounds. They are usually difficult to separate.
What do we call the bond made by a metal and non-metal?
This is called an ionic bonding.
The metal loses electrons to form a positive ion and the non-metal gains some electrons. The opposite forces attract.
What do we call the bond made by a metal and metal?
This is called metallic bonding. The metals form positive ions by loosing electrons. These electrons form a sea of delocalised electrons around the ions, holding the metals together.
What do we call the bond made by a non-metal and non-metal?
This is called covalent bonding. Each atom shares an electron with another as both nuclei are pulling the electron.
What is a Chemical Formula?
Th Chemical Formula is the letters used to symbolise a compound. For example 1 Sodium Atom (Na) plus 1 Chlorine Atoms (Cl) creates Sodium Chloride. The formula for this is NaCl. If there is more than one of either atom, there will be a small number symbolising it to the left corner of the symbol. If there is more than one molecule, there will be a large number in front of the formula.
What are the two types of ways of showing Chemical Equations?
Word Equations
Symbol Equations
What is a Word Equation?
This is when you write the name of the elements reacting (on the left), then an arrow (showing the reaction) and finally the written name of the product(s).
What is a Symbol Equation?
This is when you write the symbols of the elements reacting (on the left), then an arrow (showing the reaction) and finally the symbols of the product(s). These must be balanced.
What does it mean if a Symbol Equation is balanced?
Balancing is important for all symbol equations, this is due to the law of conservation of mass. If an equation is balanced it means there is an equal amount of each element on either side of the equation. For example if there is 1 carbon atom reacting to make 1 carbon dioxide molecule, there must also be 2 oxygen molecules reacting.
What is the Law of Conservation of Mass?
Conservation of mass states that mass can neither be created nor destroyed.
What is Chromatography used to separate?
Dyes in an ink
Describe the process of Chromatography.
1) Draw a pencil line near the bottom of filter paper
2) Add a spot of ink along the line and place the sheet in a solvent (e.g water) without the ink entering the liquid
3) Place a lid on the top to prevent evaporation
4) Any insoluble dyes will stay at the line and the colours will separate up the paper depending on how soluble that are.
5) The end result is called a chromatogram
(See Figure 4)
What is Filtration used to separate?
Separate an insoluble solid from a liquid.
Describe the process of Filtration.
1) Fold paper into a triangle and place it in a funnel
2) Place the funnel in a beaker
3) Pour in your solution
4) The insoluble solid will be left in the filter paper and the liquid in the beaker
(See Figure 5)
What is Evaporation used to separate?
To separate a soluble solid from a set solution.
Describe the process of Evaporation.
1) Pour the solution into an evaporating dish
2) Slowly heat the solution, the solvent will evaporate and become more concentrated
3) Crystals will begin to form
4) Keep evaporating until dry crystals are left
(See Figure 6)
What is Crystallisation used to separate?
To separate a soluble solid from a set solution.
Describe the process of Crystallisation.
1) Pour the solution into an evaporating dish and heat gently
2) When crystals start form, remove and allow to cool
3) Filter the crystals out of the solution and leave in a warm place to dry. You could also use a drying oven or a desiccator
(See Figure 7)
What is Simple Distillation used to separate?
Separate a mixture of two (+) liquids with different boiling points.
Describe the process of Simple Distillation.
1) Heat the solution, the liquid with the lower boiling point will thus evaporate
2) The evaporated liquid will enter a condenser with cold water and condense
3) When the thermometer shows you have reached a high enough temperature for the first to have fully evaporated, switch of the heat and allow to cool.
4) The liquid with a higher boiling point will be left in the flask with the other in a beaker at the end of the condenser.
(See Figure 8)
What is Fractional Distillation used to separate?
Separate a mixture of two (+) liquids with more similar boiling points. (too close for simple distillation)