Chapter 3 - Periodic Properties of Elements

Question 1

Who summarised the elements by periodic law effectively creating the modern day periodic table?

Answer 1

Dmitri Mendeleev

Question 2

How are elements listed in periodic table?

Answer 2

by increasing atomic number

Question 3

What are rows on the periodic table called?

Answer 3

periods

Question 4

What do all elements in a period have?

Answer 4

same number of shells

Question 5

What are columns on the periodic table called?

Answer 5

groups - have similar properties

Question 6

What do the sides of the periodic table largely consist of?

Answer 6

left = metals, right = non-metals

Question 7

What is electron configuration?

Answer 7

the use of the 4 quantum numbers to account for all electrons in an atom and designate which orbitals they occupy

Question 8

What is the Pauli exclusion principle?

Answer 8

no 2 electrons in an atom can have the same 4 quantum numbers

Question 9

What are orbitals in the same principal energy level in hydrogen?

Answer 9

degenerate (have the same energy)

Question 10

In multi electron atoms what are subshells?

Answer 10

not degenerate (energy depends on l)

Question 11

What is Coulomb’s law?

Answer 11

energy of charged particles depends on their charges and separation

Question 12

What is shielding?

Answer 12

electron repulsion in lower orbitals that screen outer electrons from nucleus
effective nuclear charge Zeffective = Z (actual charge) - S (no. of electrons shielding)

Question 13

What is penetration?

Answer 13

outer electron moves into region occupied by inner electrons

Question 14

What is the Aufbau principle?

Answer 14

a guide for determining the filling order of orbitals

Question 15

What are the 3 rules of the Aufbau principle?

Answer 15

lower-energy orbitals fill before higher energy orbitals
an orbital can only hold 2 electrons which must have opposite spins (Pauli exclusion principle)
If two or more degenerate orbitals are available follow Hund’s rule

Question 16

What is Hund’s rule?

Answer 16

if 2 or more orbitals with the same energy are available, one electron goes into each until all are half full

Question 17

What are core electrons?

Answer 17

electrons in lower-energy shells

Question 18

What are valance electrons?

Answer 18

electrons in all the sublevels with the highest principle energy shell

Question 19

What is the significance of valance electrons?

Answer 19

one of the most important factors in how an atom behaves both chemically and physically - periodic table is designed to quickly identify valance electrons

Question 20

what are the s block elements?

Answer 20

groups 1 and 2

Question 21

what are the p block elements?

Answer 21

groups 3 to 8

Question 22

What are the d block elements?

Answer 22

columns 3 to 12

Question 23

What are the f block elements?

Answer 23

lanthanides and actinides

Question 24

What are the 2 exceptions with electron configuration?

Answer 24

Chromium and Copper

Question 25

What is the electron configuration of Chromium?

Answer 25

[Ar] 4s^1 3d^5

Question 26

What is the electron configuration of Copper?

Answer 26

[Ar] 4s^1 3d^10

Question 27

What are noble gasses?

Answer 27

group 8 (8 valance electrons apart from Helium with 2) especially non reactive due to filled outer shells

Question 28

What are group 1 elements called?

Answer 28

Alkali metals

Question 29

What are group 2 elements called?

Answer 29

Alkali Earth metals

Question 30

What are group 7 elements called?

Answer 30

Halogens

Question 31

If losing or gaining electrons are they likely to fill up highest orbital d first or the highest s orbital?

Answer 31

highest orbital d will fill first, so will lose electrons from s orbital first

Question 32

What does Paramagnetic mean?

Answer 32

contains unpaired electrons attracted to magnetic field

Question 33

WHat does Diamagnetic mean?

Answer 33

contains paired electrons not attracted to magnetic field

Question 34

What trends do atomic size follow?

Answer 34

down group = radius increases across period (right) = radius decreases

Question 35

Why do as moving down a group the radius increase?

Answer 35

valence electrons occupy occupy larger orbitals and therefore the atomic size increases

Question 36

Why do as moving across a period (right) why does radius size decrease?

Answer 36

both the nuclear charge and the number of electrons increases core electrons shield outer electrons but outer electrons don't shield one another atomic size decreases across (right) the row because the effective nuclear charge increases

Question 37

What are cations?

Answer 37

when an atom has lost electrons

Question 38

What is the comparison between neutral atoms and cations?

Answer 38

cations atomic radius is smaller than corresponding neutral atoms

Question 39

What are anions?

Answer 39

when an atom has gained electrons

Question 40

WHat is the comparison between neutral atoms and anions?

Answer 40

adding electrons increases the size of the of the atom, much larger than corresponding neutral atoms

Question 41

What is Ionisation energy?

Answer 41

the amount of energy required to remove an electron from an isolated neutral atom in the gaseous state

Question 42

What happens to ionisation energy as you go down a column?

Answer 42

it decreases as valence electrons are farther away from nucleus, so electrons less shielded by nucleus

Question 43

As you move across a row (right) what happens to Ionisation Energy?

Answer 43

increases ionisation energy as increased attraction of electrons

Question 44

What are some of the exceptions to the ionisation energy laws?

Answer 44

Boron has a lower Ionisation energy than Beryllium due to a smaller Zeff (2p orbital penetrates less into 1s orbital) (as 2p found further from nucleus) Oxygen and Nitrogen Sulfur and Phosphorous (etc.) (oxygen has a paired electron in the p orbital and with only 1 electron, there is an energy penalty for a paired electron so decreases ionisation energy

Question 45

What is Electron affinity?

Answer 45

energy change when an atom in the gaseous state gains an electron

Question 46

What are the trends of electron affinity?

Answer 46

moving down a column, electron affinity decreases (electron farther from the nucleus) - this only applies for alkali metals moving across a row (from left to right) - electron affinity increases

Question 47

What is an exception to trends of electron affinity?

Answer 47

Nitrogen - less favourable affinity than neighbours - 1s and 2s orbitals full 2p orbitals all half full

Question 48

What are the properties of metals?

Answer 48

malleable and ductile shiny, lustrous, reflect light conduct heat and electricity most oxides basic and ionic form cations in solution lose electrons in reactions - oxidised

Question 49

How does metallic character trend on the periodic table?

Answer 49

increases as we go down increases going from right to left

Question 50

What are the properties of non metals?

Answer 50

brittle in solid state dull, non reflective, solid surface electrical and thermal insulators most oxides acidic and molecular form anions and polyatomic anions gain electrons in reactions - reduced