2.2.1.-Electron structure

Question 1

define atomic orbital

Answer 1

a region around nucleus that can hold up to 2 electrons with opposite spins

Question 2

define electron configuration

Answer 2

arrangement of electrons in these energy levels for an atom or ion

Question 3

electron configuration order

Answer 3

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5

Question 4

describe why lone pairs repel strongly than bonded pairs

Answer 4

-lone pairs slighlty closer to central atom and occupies more space than bonded atom
-so repels strongly than b pair

Question 5

describe the electron pair repulsion theory

Answer 5

-electron pairs surrounding the central atom determine molecule /ion shape
-pairs repel eacjhother so they are arranged as far apart as possible
-arrangement minimises repulsion,so holds atoms in definite shape
-different number of electron pairs meams different shape

Question 6

why do atoms of different elements have differenet masses?

Answer 6

have different number of neutrons and protons

mass number
protons plus neutrons

Question 7

why are mass numbers in periodic table not always whole numbers?

Answer 7

-some elements exists as isotopes so can have slightly doffernent number of neutrons

Question 8

what would happen if we change number of protons of an element?

Answer 8

number of protons determined by atomic number
so would change into a different element

Question 9

what remains the same in isotopes?

Answer 9

the number of protons and electrons
-in ions electrons change remember

Question 10

water of crystilisation

Answer 10

water molecules that make up part of crystal structure of a solid

Question 11

What is the only element which does not follow the blocking rules

Answer 11

Helium-highest sub shell is in the s-orbital when it is actually placed in the p-orbital

Question 12

number of electrons in a shell equation vs number of electrons in a sub-shell equation

Answer 12

number of electrons in shell-2n2
number of electrons in sub-shell-2n