electronic structure

Question 1

how many electrons in first three shells

Answer 1

2,8,18

Question 2

does energy increase or decrease in shells further away

Answer 2

increase

Question 3

do orbitals have different energies

Answer 3

yes

Question 4

what type of orbital are there

Answer 4

spd

Question 5

s

Answer 5

2 e

Question 6

p

Answer 6

6 e

Question 7

d

Answer 7

10

Question 8

how do orbitals fill

Answer 8

singly at first

Question 9

why do they fill singly first

Answer 9

because they are more attracted to the nucleus when not half filled

Question 10

spin

Answer 10

two e in orbitals must have opposite spin

Question 11

electronic structure of sodium (11 e)

Answer 11

1s2 2s2 2p6 3s1

Question 12

calcium (20 e)

Answer 12

1s2 2s2 2p6 3s2 3p6 4s2

Question 13

what is filled first the 4s or 2p orbital

Answer 13

4s

Question 14

sodium ion (10 e)

Answer 14

1s2 2s2 2p6

Question 15

The element nitrogen forms compounds with metals and non-metals.Nitrogen forms a nitride ion with the electron configuration 1s2 2s2 2p6 Write the formula of the nitride ion.

Answer 15

N3- / N-3

Question 16

An element forms an ion Q with a single negative charge that has the same electron configuration as the nitride ion.Identify the ion Q.

Answer 16

F–/ fluoride

Question 17

Use the Periodic Table and your knowledge of electron arrangement to write the formula of lithium nitride.

Answer 17

Li3N / NLi3

Question 18

Calcium nitride contains 81.1% by mass of the metal. Calculate the empirical formula of calcium nitride. Show your working.

Answer 18

81.1 / 40.1 18.9 / 14=2.02 =1.351.5 or 3:2Ca3N2

Question 19

Write an equation for the reaction between silicon and nitrogen to form silicon nitride, Si3N4

Answer 19

3Si+2N2 →Si3N4

Question 20

There are trends in the properties of the elements, and of their compounds, both across periods and down groups in the Periodic Table.There is a general increase in the values of the first ionisation energies of the Period 3 elements Na to Ar.State the meaning of the term first ionisation energy of an element

Answer 20

Energy/enthalpy required to remove one electron / energy/enthalpy change when one electron is removedFrom a gaseous atom;Enthalpy required/change for M(g) → M+(g) + e

Question 21

Explain this general increase in the values of the first ionisation energies

Answer 21

Increase in number of protons/nuclear chargeDecrease in size / e- closer to nucleus same/similar shielding / same shells

Question 22

Explain why the value of the first ionisation energy of Al is lower than that of Mg

Answer 22

Electron removed from 3p orbital/sub-shell in Al rather than 3s in MgAl loses e- which is of higher energy /is further away from nucleus /is shielded by 3s electrons

Question 23

There is a trend in the solubility in water of the Group II metal hydroxides.State the observations you would make when dilute aqueous sodium hydroxide is added to separate aqueous solutions of MgCl2 and BaCl2Observation with MgCl2(aq) Observation with BaCl2(aq)

Answer 23

MgCl2(aq) White ppt/solid formedBaCl2(aq) No change/no ppt/clear solution

Question 24

The hydrogen halides contain polar covalent bonds.State what is meant by the term polar as it applies to a covalent bond.

Answer 24

(A covalent bond in which) the electron density is unequally shared

Question 25

Explain why the H–Cl bond is more polar than the H–I bond

Answer 25

Greater difference in electronegativity in HCl / Cl more electronegative than ISo electron density more strongly drawn towards the Cl (than towards the I)