The quantum model of the atom

Question 1

What is the uncertainity principle?

Answer 1

measuring the position, speed, and direction of an electron is impossible.

Question 2

What is the energy of a free elctron?

Answer 2

we say it is 0, because w ecant tell, due to the uncertainity principle.

Question 3

What is an orbital?

Answer 3

A place where the electron is 95% likely to be

Question 4

how many orbitals are there on the first energy level?

Answer 4

1 orbital.

Question 5

how many orbitals are there on the second energy level?

Answer 5

4 orbitals.

Question 6

how many orbitals are there on the third energy level?

Answer 6

9 orbitals

Question 7

how many orbitals are there on the fourth energy level?

Answer 7

16 orbital levels

Question 8

What is a sublevel?

Answer 8

when we group orbitals, by similar appearence , we call them sublevels.

Question 9

How many sublevels are there in total? and name each one of them.

Answer 9

There are 4 sublevels in total.

S , P , D , F.

Question 10

Describe how the sublevels are arranged in each energy level.

Answer 10

1st energy level: 1S.
2nd energy level : 2S , 2P.
3rd energy level: 3S , 3P , 3D.
4th energy level; 4S , 4P , 4D , 4F.

Question 11

How many electrons fit in each orbital.

Answer 11

2 electrons.

Question 12

How do S - orbitals look like?

Answer 12

They are shaped like a sphere.

Question 13

How do P - orbitals look like?

Answer 13

They are shaped like a dumbell.

Question 14

Why does the energy of the sublevels, increase, as we go up the energy levels?

Answer 14

Because as we go up the energy levels, there are now more electrons repelling each other, and the ammount of repulsion between the two electrons, is affected by the shape of the orbitals they are in.

Question 15

Describe how. a graph of increasing energy in sublevels, across increasing energy levels, would look like.

Question 16

How many rules are there in order to predict an elements electron configuration? and name them.

Answer 16

There are 3 total rules:

1. The Aufbau principle.
2. The Pauli exclusion principle.
3. Hands rule.

Question 17

What is the Aufbau principle?

Answer 17

Electrons, firstly occupy the lowest energy sublevels available.

Question 18

What is the Pauli exclusion principle?

Answer 18

Each orbital can contain, either NO electrons, one electron, or two electrons. But, NEVER more.

Question 19

How many electrons can an S - sublevel have?

Answer 19

maximum 2 electrons

Question 20

How many electrons can a P - sublevel have?

Answer 20

Maximum of 6 electrons.

Question 21

How many electrons can a D sublevel have?

Answer 21

Maximum 10 electrons

Question 22

How can we divide the periodic table into blocks?

Answer 22

Each block represents the orbital in which the last electrons are found.

Question 23

describe how the periodic table is divided into blocks.

Question 24

What is the shorthand electron configuration?

Answer 24

When we identify the previous noble gas, and use that to write down the electron configuration.

Question 25

Describe all the steps to find out the shorthand electron configuration, of an element.

Answer 25

Step 1: Identify the noble gas before the element.
Step 2: Write all the sublevels, associated with the row of the periodic table, the element is in.

Question 26

What are the two types of spin? and how do we represent them?

Answer 26

1. Spin up.
2. spin down.

Question 27

What is Hunds rule?

Answer 27

1. Within a sublevel, every energy level is singly occupied, before any of them are double occupied.
2. All electrons in singly occupied orbitals, have the same spin.

Question 28

Explain why hunds rule works.

Answer 28

Because electrons in the same orbital, repel each other more than electrons in different orbitals, and so, electrons occupy different orbitals in the same sublevel, in order to reduce repulsion.

Question 29

Which elements are exceptions to the rules?

Answer 29

Copper and Chromium.

Question 30

Explain how and why chromium does NOT obey the rules.

Answer 30

Instead of it being [Ar] , 4s2, 3d4,
we say it is,
[Ar], 4s1, 3d5.
This is because the D sublevel is much more stable when it is hald full, therefore we take one electron from the 4s sublevel.

Question 31

Explain how and why copper does NOT obey the rules.

Answer 31

Instead of it being [Ar] 4s2, 3d9.
We say it is,
[Ar] 4s1, 3d10
This is because the d sublevel, is more stable when it is full, therefore, we take one electron from the 4s sublevel.