Question

Patinat, in oron:
There was a man sitting
the waiting room
Das he live
the third floor?
Write your name
the top of the page
Turn right
the next corner
There is a cafe
the corner of the street
All these books are available
CD-ROM
Were you
Mr. Raman's party?
I had a cup of coffee
Mary's house
I bought these cups
the supermarket
We waited
the bus stop for half an hour.
The dogs
the back of the car.
She put the stool
the corner of the room
a Helse
a small village
the mountains
43 Patel Street. His uncle lives
The map is
Museum Street
page 48​

Answer 1

You can also find the core and valence electrons by determining or looking up the electron configurations of the main group elements. The atomic number is the number of protons in the nuclei of the atoms of an element. A neutral atom has the same number of electrons as protons. We can look at period 2 as an example.

Answer 2

Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.