Question

8.Who was the scientist who arranged the elements in horizontal rows according

to the increasing atomic masses?

a. John Dalton

c. Dmitri Inovich Mendeleev

b. Johann Wolfgang Dobereneir

d. John Alexander Newlands

___ 9. Which orbital is being filled in the lanthanide series of elements?

a. 4f

c. 5f

b. 4d

d. 5d

___ 10. Which of the following sets is a set of all metals?

a. S, Li, C

c. K, Li, Na

b. He, Be, Ne

d. Ca, Cr, Co

___ 11. What do you call the vertical column of the periodic table?

a. a period

c. a group

b. a row

d. none of these

___ 12. Which family of elements includes helium and neon?

a. Noble gases

c. Halogens

b. Alkali metals

d. None of these

___ 13. What family of elements includes fluorine and chlorine?

a. Noble gases

c. Halogens

b. Alkali metals

d. None of these

___ 14. How many electrons are there in an atom of an element in Period 4 group VII

A?

a. Four

c. Six

b. Five

d. Seven

___ 15. Which of the following elements reacts by gaining an electron?

a. He

c. F

b. Be

d. Na​

Answer 1

Answer:

ans 8: John Alexander Newlands

ans 9:

Explanation:

8: In 1866, John Newlands, an English scientist, arranged the then known elements in the order of increasing atomic masses.

Answer 2

Answer:

8. d. John alexander newlands

9. c. 5f

10. d. ca, cr, co

11. c. a group

12. a. noble gases

13. c. halogens

14. 4

15. na

hope it helps u a lot