Which of the following is
true about an element that
has an atomic numbers of
15?
Element belongs to group 5
Element has a valency of 3
Element is a non-metal
Both [2] and [3]
Answers
Answer:
both 2 and 3 is right. option.
Explanation:
Given elements electronic configuration is- 1s² 2s² 2p⁶ 3s² 3p³
from this info the element is in 3nd period because highest principal quantum number [number before the alphabet] is 3.
looking at the alphabet we get to know the element is in p block [13-18 group]
to find group in p orbital use formula 10 + electron in Valence shell(top numbers) 10 + (3+2) = 15 group
Anyways with this info you can pretty much do anything... group is not 5. Valency = 8-5 = 3. Element lies in p block hence is very much a non metal.
hence answer is D
if your in 10th then just remember the element from 1 to 20 enough and you can answer most of the questions. but if in puc learn the top method then you can solve any problem. I take it your in 10th so just learn 1-20 elements and their valency you will be able to answer.
oh an don't forget calcium is a metal I didn't know till like 10th and lost one mark when they asked if it was a metal or nonmetal.
hope this helped.