electron structure

Question 1

define an atomic orbital

Answer 1

a region within an atom arround the nucleus that can hold up to 2 electrons with opposite spins

Question 2

define a shell

Answer 2

a group of atomic orbitals with the same principle quantum number n

shell closest to nucleus has lowest energy and quantum number of 1

Question 3

whats the max number of electrons the 1st shell can hold? and orbitals?

Answer 3

2 electrons
1 orbital

Question 4

whats the max number of electrons can the 2nd shell hold? and orbitals?

Answer 4

8 electrons
4 orbitals

Question 5

whats the max number of electrons the 3rd shell can hold? and orbitals?

Answer 5

18 electrons
9 orbitals

Question 6

whats the max number of electrons the 4th shell can hold? and orbitals?

Answer 6

32 electrons
16 orbitals

Question 7

what is a subshell?

Answer 7

a group of the same type of atomic orbitals within a shell

Question 8

what does an s orbital look like?

Answer 8

spherical shape

Question 9

what does a p-orbital look like?

Answer 9

a dumb-bell shape

Question 10

what does a p-subshell look like?

Answer 10

-from n=2 upwards, each shell contains 3 p-orbitals at 90 degrees to one another along the x-,y- and z- axes

-this gives a total of 6p electrons in the p-sub-shell

-each p orbital has a 3D dumb-bell shape with its centre at the nucleus

Question 11

what does a d orbital look like?

Answer 11

-from n=3 upwards, each shell contains 5 d-orbitals
-this gives a total of 10d electrons in a d sub-shell

Question 12

what is the aufbau principle?

Answer 12

electrons fill orbitals of lowest energy first

Question 13

why does 4s orbital fill before 3d?

Answer 13

because the 4s sub-shell has a lower energy than the 3d sub-shell

Question 14

what is the order of filling orbitals?

Answer 14

1s^2,2s^2,2p^6,3s^3,3p^6,4s^2,3d^10,4p^6

Question 15

what is the electron configuration of Mg?

Answer 15

1s^2,2s^2,2p^6,3s^2

Question 16

describe the relative energies of the 2s orbital and each of the three 2p orbitals in a nitrogen atom

Answer 16

-P-orbitals have greater energy than s-orbitals
-three p-orbitals have equal energy

Question 17

properties of electrons

Answer 17

-negatively charged
-have spin = electrons in an orbital have opposite spins

Question 18

what are the diffences in electrons with positive and negative ions?

Answer 18

-when positive ions are formed, electrons are removed from the highest energy orbitals
-when negative ions are formed, electrons are gained to the highest energy orbitals

Question 19

what makes Cr and Cu more stable?

Answer 19

they have full and half-full 4s and 3d sub-shells

Question 20

how can a d-sub-shell be incomplete?

Answer 20

if its full
if its empty

Question 21

define a transition element

Answer 21

a d-block element that forms an ion with an incomplete d sub-shell

Question 22

what happens when transition elements form cations?

Answer 22

they lose their 4s electrons first

Question 23

why arent Zn and Sc transition metals?

Answer 23

Sc3+= …..3p^6. this ion has an empty d sub-shell therefore not incomplete
Zn2+=……..3d^10. this ion is completely full therefore not incomplete