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25 Cards in this Set
- Front
- Back
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What is an element? |
An element is a substance which cannot be broken down into simpler substances by chemical means |
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What are examples of elements? |
Iron (fe), zinc (zn), aluminium (al), silver (ag), gold (au), copper (cu), sodium (na) |
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What is an atom? |
And atom is the smallest part of an element that still has properties of that element |
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What is a compound? |
A compound is formed when two or more elements combine chemically |
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What is an example of a compound? |
Table salt |
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Why is it a compound? |
Because it is made up of two diffrent types of atom in this case - sodium and chlorine = table salt = NaCl |
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What is a mixture? |
A mixture consists of two or more substances mingled together but not chemically combined |
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What are examples of mixtures? |
Air; nitrogen, oxygen, carbon dioxide Seawater; water and salt Ink; water and various dyes Steel; iron and carbon Earth; stones, sand, clay, water |
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What is the diffrence between a mixture and a compound? |
Mixtures can be easily separated whereas compound are very difficult to separate |
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What is a physical change? |
It is a change where no new substances is formed e.g melting ice, cutting paper |
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What is a chemical change? |
It is a change where new substances is formed e.g rusting of iron, rusting of paper |
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What is a molecule? |
It is thr smallest part of an element or compound that can exist on its own e.g magnesium oxide (MgO), water (H2O), carbon dioxide (Co2), |
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What are halogens? |
They are group 7 of the periodic table e.g chlorine and iodine. These non metals form ions with a positive charge |
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Name some everyday examples where you can find chlorine and iodine |
Bleaches, disinfectants, salts |
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What are noble gases? |
They are group 8 of the periodic table e.g helium (He) and neon (Ne) |
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Name some everyday examples where helium and neon are used |
Lighted signs, refrigerants and lasers |
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Are noble gases reactive? |
No, because they have a little tendency to gain or lose electrons |
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What is a period? |
A period is a horizontal row of elements in the periodic table |
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What is the atomic number? |
It is the number of protons in the nucleus of the atom |
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What are groups? |
Groups are elements that have the same outer electron arrangement |
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What are the characteristics of group 1- alkali metals |
The alkali metals are highly reactive They are stored under oil Low density Soft = can be cut with a knife Burn in air to form oxides React with water to form hydroxides |
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What are examples of alkali metals? |
Sodium (Na) and potassium (K) |
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What do alkali metals form? |
They form salts and many other compounds |
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What are alkaline earth metals? |
They are located in group 2 of the periodic table e.g calcium (Ca) and magnesium (Mg). They form many compounds |
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What are the characteristics of group 2 - alkaline earth metals |
Group 2 Reactive Harder than group one Burn in air to form oxides React with water to form hydroxides |
