Chemistry Revision

2. The atoms of halogens are……
4. He discovered the electron
7. What is the common name for CaCO3
9. The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms, including nitrogen fixation and decomposition
12. Which gas turns limewater milky?
13. The time it takes for half of the atoms of a substance to decay
17. A radioactive isotope used in the treatment of cancer
18. The elements between the groups 2 and 3 are called the
20. What are the group seven elements called?
21. This process is used to find the age of dead organisms by comparing the amounts of two isotopes of carbon.
23. What is the flame colour for potassium
24. Plants can create most of the world’s free oxygen through this process
26. This element is used to make nuclear power
27. This is one of the types of subatomic particle

1. The fourth alkali metal
3. A type of bonding where electrons are transferred from one atom to another
5. What is the seventh element in the periodic table.
6. Transition can be hammered into shape without breaking. They are ……
8. woman discovered radium?
10. A type of bonding where the electrons are shared
11. Oxygen and nitrogen can be obtained from liquid air by a process called…
14. One of the allotropes of carbon which is used in jewellery
15. The emission of energy as electromagnetic waves or moving subatomic particles
16. The ore that pure uranium and pure radium can be obtained from.
19. Hydrogen burns with a……
22. The space an electron occupies is called an
25. Elements with the same number or protons and electrons but different numbers of….