2. What refers to the positively charged subatomic particle?

3. What refers to the negatively charged subatomic particle?

4. Who suggested that all matter is made up of atoms, which were indivisible and indestructible?

5. Who suggested that an atom consists of a small nucleus (positively charged) surrounded by negative electrons moving around the nucleus in orbits?

6. Who assumed that an electron is two thousand times lighter than a proton and believed that an atom is made up of thousands of electrons?

7. Who proposed the plum pudding model of atom?

8. According to Rutherford, electrons revolve around the nucleus in fixed paths. What do you call these fixed paths?

9. Who proposed the modern theory of atom?

10. Which refers to the arrangement of electrons in energy levels around an atomic nucleus?

11. Which of the following is the electron configuration of the element Cobalt (CO) 27?

12. Which of the following is the electron configuration of the element Scandium (SC) 21?

13. What refers to the table of the chemical elements arranged in order of atomic number?

14. Who published the first version of periodic table?

15. What do you call the rows of elements in the periodic table?

16. What do you call the columns of elements in the periodic table?

17. What do you call the number of protons that can be found in the nucleus of an atom?

18. Which reacts violently with water, forming hydrogen gas and the metal hydroxide?

19. Which are highly reactive metals?

20. Which of the following is NOT a halogen?

21. Which is the most reactive halogen?

22. Which are used in batteries because it is a light element and pro duces a higher battery voltage?

23. Which are found in human teeth and bones, hard water, and limestone and also an ingredient in cement?

24. Which has halogen is a yellow–green gas, extremely poisonous, and has a stifling, pungent odor?

25. Which of the following are the noble gases?