Electrons And Bonding- Electron Structure

Question 1

What are shells?

Answer 1

• shells are regarded as energy levels
• energy increases and shell number increases
• the shell number is called the principal quantum number, n

Question 2

How many electrons maximum can be held in each shell?

Answer 2

-n1 holds 2
-n2 holds 8
-n3 holds 18
-n4 holds 32
It goes by the formula: 2n squared

Question 3

What is an atomic orbital?

Answer 3

Shells are made up of atomic orbitals. An atomic orbital is a region around the nucleus that can hold up to two electrons, with opposite spins.

Question 4

Describe an s-orbital

Answer 4

In an s-orbital the electron cloud is the shape of a sphere. It can hold 1 or 2 electrons. Each shell from n=1 contains one s-orbital. The greater the shell number, the greater the radius of its s-orbital.

Question 5

Describe a p-orbital

Answer 5

The electron cloud is within the shape of a dumbbell sign. P orbitals can only hold 1 or 2 electrons. There are three separate p-orbitals, one at the y-axis, one at the x-axis and one diagonal.

Question 6

d- and f- orbitals

Answer 6

• each shell from n=3 contains 5 d-orbitals

- each shell from n=4 contains 7 f-orbitals

Question 7

does each new sub shell have more energy than the previous one?

Answer 7

yes and within a sub-shell the orbitals have the same energy.

Question 8

why are orbitals of the same sub-shell occupied singly first?

Answer 8

this prevents any repulsion between paired electrons until there is no further orbital available.

Question 9

the order of sub shells in electron configuration

Answer 9

1s( shell 1), 2s and 2p (shell2), 3s and 3p(shell 3), 4s(shell 4), 3d(shell 3), 4p(shell 4)

Question 10

why is 4s before 3d when it is in shell 4?

Answer 10

because it has a lower energy level

Question 11

how many electrons max does each orbital of a subshell hold?

Answer 11

shell 1: 1s holds 2 electrons
shell 2: 2s holds 2 electrons and 2p holds 6 electrons
shell 3: 3s holds 2 electrons, 3p holds 6 electrons and 3d holds 10 electrons
shell 4: 4s holds 2 electrons and 4p holds 6 electrons

Question 12

how is the electron configuration always written?

Answer 12

in order of shells

Question 13

What is short hand notation?

Answer 13

when electron configuration is done more simply in terms of the previous noble gas plus the outer electron sub shells

Question 14

when d- block elements(transition metals) lose electrons…

Answer 14

the electrons are lost from the 4s sub shell before the 3d sub shell

Question 15

what is the first ionisation energy?

Answer 15

the energy required to remove one electron from each atom in one mole of gaseous atoms

Question 16

what are the different blocks in the periodic table and what do they represent?

Answer 16

there is a s-block, d-block, p-block and f-block. The blocks represent which sub shell the elements have the highest energy electron.

Question 17

where is the s, p, d, f block found on the periodic table?

Answer 17

s block- group 1 and 2 and He
d block-transition metals
p block- 3to 0 group
f block- two bottom row