Atomic Orbitals and Electronic Configurations

Question 1

what did max planck’s quantum theory state

Answer 1

• electrons can only exist in certain well defined energy levels
• these are called quantum shells

Question 2

what do all electrons in a given quantum shell have

Answer 2

• similar energy levels

- but not necessarily equal or identical

Question 3

how does the energy of electrons in the first quantum level of an atom of an element compare to the others and why

Answer 3

• they have the lowest energy

- as they are closest to the nucleus

Question 4

what significantly differentiates the first quantum level from the second, third and so forth (which are progressively further away from the nucleus)

Answer 4

• the first quantum level is the only level without multiple sub shells
• the following levels have multiple sub shells with different energy levels

Question 5

what is the only subshell in the first quantum level labelled as

Answer 5

1s

Question 6

how many subshells does the second quantum level have and what are they labelled

Answer 6

• it has two

- which are labelled 2s and 2p

Question 7

how do the energy levels of the electrons in the 2p subshell compare to those in the 2s subshell

Answer 7

the electrons in the 2p subshell have slightly higher energy levels than the electrons in the 2s subshell

Question 8

how many subshells is the third quantum level divided into and what are they labelled as

Answer 8

• it has three subshells

- which are 3s, 3p, and 3d

Question 9

how do the energy levels of the electrons in the 3d subshell compare to those in the 3p subshell

Answer 9

the electrons are at slightly higher energy levels than those in 3p

Question 10

how many subshells does the fourth quantum level have and what are they labelled as

Answer 10

• it has four subshells

- which are 4s, 4p, 4d and 4f

Question 11

how do the energy levels of electrons in the 4d subshell compare to those in the 4f subshell

Answer 11

the electrons have slightly less energy than those in the 4f subshell

Question 12

what does each subshell contain (other than electrons)

Answer 12

orbitals

Question 13

what is the actual name of the s orbital in which two electrons are in the 2s subshell

Answer 13

the 2s orbital

Question 14

what is the difference between the 1s and 2s orbital

Answer 14

• the 2s orbital has a larger radius than the 1s orbital

- however they are both spherical

Question 15

what is the significance of the shape and sizes of the orbitals that are drawn

Answer 15

they show that there is a 90% chance of finding an electron within those boundaries

Question 16

how many p orbitals does the 2p subshell contain

Answer 16

3 p orbtitals

Question 17

what is the similarity and difference between the 3 p orbitals

Answer 17

• the similarity is that they all have a elongated dumbbell shape with a variable charge density
• the difference is that they all have different orientations in space (the region where you would find the electrons)

Question 18

how many d orbitals are there in a d subshell

Answer 18

5 d orbitals

Question 19

what would you actually be finding in each of these orbitals, or more like what could they hold

Answer 19

• two electrons

- spinning in opposite directions

Question 20

what would a table showing the type of subshell and the number of electrons that could be present in it look like

Answer 20

• s subshell = 2 (1 x 2)
• p subshell = 6 (3 x 2)
• d subshell = 10 (5 x 2)
• f subshell = 14 (7 x 2)

Question 21

why are the number of electrons in each subshell like so

Answer 21

• the s subshell has only 1 s orbital with two electrons in it
• the p subshell has 3 p orbitals with two electrons in it
• the d subshell has 5 d orbitals with two electrons in it
• the f subshell has 7 f orbitals with two electrons in it

Question 22

what would a table showing the quantum shell and the number of electrons look like

Answer 22

• first quantum = 2 electrons
• second quantum = 8 electrons
• third quantum = 18 electrons
• fourth quantum = 32 electrons

Question 23

knowing that different quantum shells have different combinations of subshells, decipher which subshells and orbtials the different quantum shells are made from

Answer 23

• the first quantum shell only consists 1 s subshell (1s) meaning it can only hold 2 electrons
• the second quantum shell consists of 1 s subshell and 1 p subshell (2s and 2p) meaning it has 2 + 6 = 8 electrons
• the third quantum shell consists of 1 s subshell, 1 p subshell and 1 d subshell (3s, 3p and 3d) meaning it has 2 + 6 + 10 = 18 electrons
• the fourth quantum shell has 1 s subshell, 1 p subshell, 1 d subshell and 1 f subshell (4s, 4p, 4d and 4f) meaning it has 2 + 6 + 10 + 14 = 32 electrons

Question 24

what is the electronic configuration of an atom of an element

Answer 24

the distribution of electrons among atomic orbitals

Question 25

how does the order in which the electrons fill up the orbitals compare to the way that it would normally be chronologically written

Answer 25

• the subshells fill up in the order: 1s, 2s, 2p, 3s, 3p, 4s, 3d
• but it is chronologically written (and ordered as): 1s, 2s, 2p, 3s, 3p, 3d ,4s…

Question 26

why does the 4s subshell fill up first before the 3d subshell

Answer 26

• the energy of the 4s orbital is lower than the energy of the 3d orbital
• this is because the exact energies of the electrons in the orbitals are determined by the number of protons in the nucleus of the atom
• and the repulsion of all the other electrons present

Question 27

knowing that the 4s orbital fills up first rather than the 3d orbital, what would the electronic configuration of Ca look like (it has 20 protons) and what would the wrong one be

Answer 27

• it is correctly written as: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2

- not: 1s2, 2s2, 2p6, 3s2, 3p6, 3d2

Question 28

why is the way in which Ca’s for example electronic configuration not going to matter for most elements

Answer 28

• because it only matters when the 4s subshell isnt full yet
• it it was Ti for example with 22 protons its e.c. would just look like:
• 1s2, 2s2, 2p6, 3s2, 3p6, 3d2, 4s2
• the 4s is in front of the 3d as it is full anyway

Question 29

why is Cr with an atomic number of 24 a special case in terms of how its e.c. is written

Answer 29

• its e.c. would be: 1s2 2s2, 2p6, 3s2, 3p6, 4s1, 3d5
• this is because the atom of this element would be more balanced if it had one electron in the 4s subshell with one s orbtial and 5 electrons in the 3d subshell with 5 d orbitals