The BIG crossword on "Atoms and Elements" at doc brown's KS3 chemistry

FOR PRINTING OUT ONLY, answers found via KS3 chemistry link above
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Across:

1. Oxygen is in this state at room temperature. (3)
3. Is it a gas, liquid or solid? meaning the physical ? of the material. (5)
4. Made from two or more atoms combined together. (8)
6. Number of atoms in the oxygen 'particle'. (3)
8. Summarises all the atoms in a molecule. (7)
9. Just one type of atom. (7)
11. The number of naturally occurring elements (5,3 because I forgot an e, and I'm not starting again!)
14. The only liquid metal element at room temperature, known as 'quicksilver'. (7)
15. The main gaseous product of burning coal in air, two elements combine. (6,7)
16. Its a way of splitting a compound, just turn on the current and turn up the voltage! (12)
18. A very reactive metal with water. (6)
20. This element burns very brightly in air to form a white powder. (9)
21. Nearly the last metallic element in the alphabet and used in batteries. (4)
25. This type of element usually has a low melting point and poor heat conduction. (8 or 3,5)
26. This type of compound is usually formed when you burn an element in air. (5)
27. This element glows very nicely when you put a high voltage of electricity through it! (4)
30. Nearly the symbol for cobalt, 'small' error in 2nd letter! but the formula of a very toxic gas! (2)
31. The proper chemical name for 'salt' formed from combining two elements. (6,8)
32. Oh!!! to get the 1st letter of this element on a triple score in scrabble! (5)
33. Only two elements are in this state at room temperature! (6)
34. Poor lonely helium, only ? atom(s) to the 'molecule'! (3)
36. A metal alloyed with iron to make tough steels. (9)
37. This type of element usually has a high boiling point and good electrical conduction. (5)

Down:

2. The simplest bit of an element that is an element! (4)
3. The state of the element sulphur at room temperature. (5)
4. Iron is this, but aluminium is not! (8)
5. Formed when two or more elements chemically combine together. (8)
7. Formed by combining the elements hydrogen and oxygen. (5)
8. The number of oxygen atoms in a sulphuric acid molecule. (4)
10. Dark red, and the only liquid non-metal at room temperature. (7)
12. The number of atoms in a water molecule. (5)
13. A very useful 'layout' of all the elements. (8,5)
17. Every element has one as well as its name! (6)
19. This elements sets the world alight! thank you plants! (6)
22. Its a pity this element rusts a bit too readily! (4)
23. The main element in fossil fuels like coal. (6)
24. A nasty green gas but good for killing bacteria in water! (8)
28. The number of atoms in a methane molecule. (4)
29. A solid non-metal, very dark coloured, gives a purple vapour on heating, but looks yellow-brown, when its 'tincture' solution is used on your skin as an antiseptic! (6)
30. A metal used since ancient times for jewellery, very pretty when polished and for your thoughts! (6)
35. The formula of nitrogen dioxide. (3)