Crossword

Click on a number in the grid to see the clue or clues for that number.
If you are stuck, you can click on "Hint" to get a free letter. You will lose marks every time you get a hint.
When the crossword is complete, click on the "Check" button.
Best of luck!
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 7        8    9    10         
 11   12                  
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 15      16             17    
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  27                  
28               29       

Across:

4. Danish physicist who made fundamental contributions to understanding atomic structure (4)
5. The type of spectrum seen when the electromagnetic radiation emitted by a substance is observed through a spectrometer. (8)
6. Element with four protons (2)
10. These tests help to identify metals (5)
11. This electrode attracts negative ions (5)
13. Symbol for manganese (2)
14. A charged atom (3)
15. Chemical symbol for chlorine (2)
17. Symbol for magnesium (2)
18. The spectrum obtained by passing light through a gaseous sample (10)
19. Chemical symbol for manganese (2)
20. Nationality of scientist who discovered radium (6)
21. Symbol for an alkali metal (2)
22. A glass which may be used to form a spectrum (5)
23. Contains a pair of electrons (7)
24. Red-brown liquid element (7)
25. A negative electrode (7)
28. Mass ____________, an instrument which can measure the masses and relative concentrations of atoms and molecules (12)
29. Describes a pair of electrons not involved in bonding (4)

Down:

1. A group of three (5)
2. Chemical symbol for lithium (2)
3. Movement of particles from an area of high concentration to an area of low concentration (9)
6. A ray of light (4)
7. Symbol for sodium (2)
8. Different atoms of the same element with different number of neutrons (7)
9. To fix the energy of an electron at a definite value (9)
12. He proposed the Law of Octaves (8)
16. He grouped elements into groups of three (10)
17. He put forward the idea Atomic Number (7)
23. Musical term or group of seven (6)
26. Millikin used drops of this in his famous experiment (3)
27. Element whose atoms hae two protons (2)