Question

1) The place of an element in the periodic table is determined by its ... ?

A) mass number B) density C) atomic numbed D) atomic mass

2) We obtain energy from the sun by

A) molecular travel

B) conduction

C) convection

D) radiation

Answer 1

1)Place of element in periodic table is determined by atomic number.

Option C

Atomic number is taken as serial number of elements. It starts from number 1 hydgrogen, number 2 helium etc.

2)We obtain energy from sun by radiation. It does not require medium. Here medium (air ) is only around earth. The remainng distance is vacuum. Conduction and convection require medium

Option D