Reactions
Atoms
Elements
Ions
The Periodic Table
100
Describe a physical change.
A physical change is when a substance changes state (it is still the same substance).
100
What is the centre of the atom called and what does it contain?
It is the nucleus, and it holds the protons and neutrons.
100
What is an element?
A substance made up of only ONE type of atom.
100
What is an ion?
An ion is an atom that has lost or gained electrons.
100
What are the horizontal rows called? What do elements in each row have in common?
Periods. They all have the same number of electron shells.
200
Describe a chemical change.
A reactant is changed into a product (a chemical reaction has occurred). It is now a different substance and is hard to change back.
200
Where are the electron shells found, and how many electrons can fit into each?
Outside the nucleus. 2 in the first shell, then 8, then 8, etc.
200
How do you draw an element's symbol?
Captial letter first, then a lowercase letter (if it has two letters in its symbol).
200
Ions that are positive have: a) lost electrons or b) gained electrons?
a) lost electrons
200
What are the vertical columns called? What do elements from the same column have in common?
Groups. Elements from the same group have the same number of valence electrons in their outer shell.
300
Give the equation for a chemical reaction.
Reactants --> Products
300
What makes up the mass number of an atom, and why?
Protons and neutrons, they are the heavy particles and so they make up the mass of the atom.
300
This element is necessary for our cells to live. It makes up 20% of the air. Name the element, give its symbol, atomic and mass number.
Oxygen, O. Atomic number=8, mass number=16
300
Why does an atom form an ion?
Because it wants to form a full outer electron shell, and become stable. So it either loses or gains electrons to get a full outer shell.
300
How is the periodic table arranged?
In atomic number order - from smallest to biggest.
400
Give an 2 examples of a physical change and 2 examples of a chemical change.
Physical - e.g. ice melting, crushing a can, breaking glass, etc. Chemical - e.g. burning toast, rusting metal, a bomb exploding, adding metal to acid, etc.
400
What are the outermost electrons called?
Valence electrons
400
This element is in Group 17, it is found as a greenish gas, and it is also used to keep swimming pools clear. Give its name, atomic symbol, atomic number, mass number, electron arrangement and number of protons, electrons and neutrons.
Chlorine, Cl. Atomic number=17. Mass number=35. Electron arrangement=2,8,7. Protons and electrons=17. Neutrons=18.
400
What ion does calcium form? Why?
Calcium forms a Ca2+ ion. This is because it has 2 electrons in its outer shell, which is wants to lose so that it can have a full outer shell. So it loses 2 electrons, becoming positive.
400
What is the smallest atom? Give its name and symbol, and its numbers of protons, electrons and neutrons.
Hydrogen, H. 1 proton, 1 electron, 0 neutrons.
500
Name 4 signs that a reaction has taken place.
New product made, heat given off, bubbling/fizzing occurs, a gas is formed, change in temperature, change in colour, light given off, a precipitate (solid) may be formed, a sound (e.g. a bang) is given off.
500
Why is the atom neutral?
Because there are equal numbers of protons and electrons in it.
500
This element is strongly reactive with water and air, yet is found in bananas. Name the element and explain why it does not react when we eat bananas?
Potassium (K). Because it is bonded to other elements, forming neutral compunds, and it is not free to react with our bodies.
500
What ions does Group 17 form? Why are they all the same?
Group 17 forms 1- ions. They all have 7 electrons in their outer shells, so they gain one more electron, forming a negative 1- ion, filling their outer shell and becoming stable.
500
What does the zig-zag line separate? Give one example and a property from each of the groups on either side of the line.
It separates metals and non-metals. Metals e.g. Na, K, Al, Ca, Zn, Ag, etc. Metals form positive ions, they conduct electricity, they are ductile, strong and malleable. Non metals e.g. O, N, F, Cl, Br, Ar, Ne, etc. Non-metals form negative ions, do not conduct electricity, form covalent bonds and break easily.
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