Question

can anyone tell me the trick to learn valency of elements?????upto 20 i know a trick but after tgat upto 30 plzzz tell...
don't post any stupid ans plzzz

Answer 1

If you know the atomic number of any element, you can easily remember their valencies according to the number of electrons remaining in their last orbit which is also known as valence electrons. You can find out the valence electrons of any element by seeing the electronic configuration which you can easily find out from its atomic number. For example: Let me take a larger atom, say Titanium The atomic number is 27. So electronic config will be 2, 8, 8, 4. We can see that the valence electrons have 4 electrons in its last orbit. So the valency of Titanium will be 4. Let us assume another example, say Iron. Electronic config is 2, 8, 8, 8. We can see​ that the octet is complete. So the valency of Iron is 0.

Hope it helps. Thank you. ☺♥

Answer 2

To find out valency (the tendency to lose or gain electron to obtain octet at the outer shell) you have to find out the number of valence electrons an element has. You can find out the valence electrons of an elementof know it's group number.
 can often help to physically point at each row as you examine it in order to develop an instinctive feel for the arrangement of the chart. Look at the leftmost column on the periodic table. It is the start of the table and the top element is hydrogen -- the building block of matter as we understand it.