1 Fundamental Ideas Flashcards
How do we represent atoms and elements?
Periodic table
What is the basic structure of an atom?
An atom has a tiny nucleus in its centre, surrounded by electrons
What is a molecule?
A grouping of two or more atoms bonded together is called a molecule
What holds together a compound?
Chemical bond
What is a compound?
A substance made when two or more elements are chemically bonded together
What is an element?2
A substance made up or only one type of atom
An element cannot be broken down chemically into any simpler substance
What is a covalent bond?
The attraction between two atoms that share one or more pairs of electrons
What is the charge on a proton?
Positive
What is the charge on a neutron?
Neutral
What is the charge of an electron?
Negative
What is the atomic number?
Number of protons
What is the mass number?
Number of protons + neutrons
What is the proton number equal to?
The number of electrons
What are elements made of?
Atoms
Why are atoms neutral?
Because the number of electrons is the same as the number of protons
How are electrons arranged inside the atom?
In energy levels (shells)
When atoms have the same number of electrons in their outer shell, what do they have common in the periodic table?
They are in the same group
Why are the atoms of group 0 elements so un reactive?
The atoms of the unreactive noble gases all have very stable arrangements of electrons
What does the number of electrons in the outer shell determine?
The way the element reacts
How many electrons does the second energy level hold?
8 electrons
What happens when metals react with non metals?
Charge particles called ions are formed
What happens to the atoms in a chemical reaction?2
As no new atoms are ever created or destroyed in a chemical reaction:
The total mass of reactants = the total mass of products
Group number?
Electrons in outer shell
Period number?
Number of rings
Name the two sub atomic particles in the nucleus of an atom?
Proton
Neutron
Why is there no overall electrical charge on each atom?
There are equal numbers of protons and electrons
What makes an atom unreactive?
Full outer shell
What is water vapour?
Hydrogen oxide
Name one instrumental method used to identify elements or compounds?
Mass spectroscopy
Advantages of using instrumental methods instead of chemical tests?
Fast Small amount Sensitive Reliable Continuous
Purpose of paper chromatography?
Separating artificial colours
Purpose of gas chromatography?
Identifies substances
And
Separates mixtures
Purpose of mass spectroscopy?
Relative molecular mass found
Substance identified
Describe mass spectroscopy?
GC machine allows the separated substances leaving the column to have their molecular mass identified
Graph drawn
Peak furthers to the right is the molecular ion peak
Describe paper chromatography?
Extract colour from food sample and place it in a cup with solvent
Spots of this solution on the PENCIL baseline on filter paper
Sheet in beaker with solvent - baseline above solvent
Solvent deeps up paper with dyes
Different peaks formed
Describe gas chromatography?
Gas carries substances though a column, filled with solid material
Substances travel through at different speeds - separating them
Time taken to reach detector at end of the tube is the RETENTION TIME
Which helps to identity substances
The recorder draws a gas chromatograph -
number of peaks shoes the number of compounds
Position of peaks shows rtention time
Roughly how many elements are there thought to be?
100
What do compounds formed from non metals consist of?
Molecules
In molecules, how are the atoms held together?
Covalent bonds
What do compounds formed from metals and non metals consist of?
Ions
How do metals react?
They lose electrons to form positive ions
How do non metals react?
They gain electrons to form negative ions
Atomic number?
Protons
Mass number?
Number of protons and neutrons
Suggest why we should recycle aluminium drink cans?
Reduce landfill
Saves resources
Less quarrying
What is meant by reduction?
Loss of oxygen
Gain of electrons t
What does making an alloy do?
Increase hardness
Decrease malleability
Increase resistance to corrosion
What makes something a good fuel?
Burns easily produces high heat energy
Easy to store or transport
Hydrogen test?
Ignite a splint
Gas burns to make a squeaky pop
Hydrogen test?
Ignite a splint
Gas burns to make a squeaky pop
What makes something a good fuel?
Burns easily produces high heat energy
Easy to store or transport
What does making an alloy do?
Increase hardness
Decrease malleability
Increase resistance to corrosion
What is meant by reduction?
Loss of oxygen
Gain of electrons t
