Written by students who passed Immediately available after payment Read online or as PDF Wrong document? Swap it for free 4.6 TrustPilot
logo-home
Lecture notes

UNIT 1; ATOMIC STRUCTURE AND THE PERIODIC TABLE NOTES

Rating
-
Sold
-
Pages
2
Uploaded on
28-06-2026
Written in
2025/2026

notes on UNIT 1 for chemistry edexcel a-level

Content preview

PARTICL Proto Neutro Electro
E n n n BOX-NOTATION
NOTE: 4s fills before 3d
Relative +1 0 -1
Charge REMOVE ONE ELECTRON THESE TWO FACTORS
When 3d starts to fill it NOBLE’STHE
NOTES
Relative 1 1 1/2000 FROM EACH ATOM IN ONE OUTWEIGHT EFFECT OF
Mass repels 4s and becomes
MOLE OF GASEOUS ATOMS INCREASES NUCELAR CHARGER.
higher in energy than 4s
TO FORM ONE MOLE OF INCREASED ATOMIC RADIUS AND
ATOMIC NUMBER- number of EXAMPLES NOTE: electrons fill up GASEOUS +1 IONS SHIEDLING WEAKENS THE
protons in an element singly for all orbitals NUCLEAR ATTRACTION OF THE
before filling up in the NUCLEUS TO THE OUTER SHELL
MASS NUMBER- number of opposite direction ELECTRONS SO LESS ENERGY IS
protons+neutrons in an
SOME OF THE RULES REQUIRED TO REMOVE
element
APPLY DIFFERENTLY TO 2 ELECTRON
FACTORS THAT AFFECT
ELEMENTS: COPPER AND
IONISATION ENERGY First ionisation energies
CHROMIUM
ORBITALS INCREASE across a period (left to
WRITING OUT MASS SPECTRA OF Copper electronic - ATOMIC RADIUS
A region of space where up right)
A MOLECULAR structure: ends in 4s¹ 3d¹⁰ The greater the distance
to 2 electrons can be found. This is because:
EXAMPLE: The electrons have - More repulsion between the nucleus and
ISOTOPES- elements with the between electron in the outer electron, the - Atomic radius decreases
Bromine has two isotopes, 79 Br OPPOSITE SPINS
same number of protons but 4s subshell weaker the nuclear - Shielding effect is similar
(50.69%) and 81 Br (49.31%), so SHAPES OF ORBITALS
differ in the number of neutrons - FULL 3D SUBSHELL attraction- LESS ENERGY - Nuclear charge increases
the mass spectrum of its
s-orbital IS MORE STABLE REQUIRED
ION- charged atom molecule, Br 2 is as follows
This results in a stronger nuclear
THAN PARTIALLY
electron cloud is in the FILLED 4S - NUCELAR CHARGE- attraction to outer electron more
CATION- positive ion (more
shape of a sphere SUBSHELL energy is required to remove it
protons than electrons) the higher the number of
ANION- negative ion (more protons in the nucleus, EVIDENCE OF SUB-SHELLS
electrons than protons)

RELATIVE ATOMIC MASS- the
Atomic the greater the nuclear
attraction
Although first ionisation energies
show a general increase across a
weighted mean mass of an - ELECTRON SHIELDING period, it falls in 2 places each
atom of an element relative to - 4S ELECTRON IS period
The more electron
1/12th the mass of an atom of PROMOTED TO 3D
shielding, the lower the EXAMPLE:
carbon-12 Chromium electronic nucelar attraction
structure ends in 3d⁵ 4s¹ between outer shell
RELATIVE ISOTOPIC MASS- the
mass of an atom of an isotope - Repulsion between electrons and the
relative to 1/12th the mass of an p-orbital 4s electrons nucleus
atom of carbon-12 - HALF FULL 3D
electron cloud is in the SUCUESSIVE IONISATION
ELECTRON STRUCTURE SUBSHELL IS
CALCULATING RAM shape of a dumbbell/ figure ENERGIES
MORE STABLE
of 8 THAN PARTIALLY Example: SECOND
FILLED IONISATION ENERGY- the
- 4S ELECTRON IS energy to remove one
PROMOTED TO 3D
electron from each ion of Beryllium and boron
EXAMPLE
SHORTHAND +1 ions, to form one mole
Use the data provided from the ELECTRONIC of gaseous +2 ions Beryllium has a full 2s subshell,
mass spectrum to find the SUBSHELL Number of e- d-orbitals and f-orbitals are CONFIGURATION- writing which is more stable and closer
relative atomic mass of chlorine s 2 much more complicated the final subshell to the nucleus than boron's 2p
p 6 electron- higher 1st IE
Subshell Number of Example 20Ca= [Ca]4s2 TRENDS OF FIRST
SEE NEXT BOX FOR DATA d 10
(f) 14 orbitals IONISATION ENERGY IONISATION ENERGIES Nitrogen and oxygen
S 1
P 3 THE FIRST IONISATION First ionisation energies - In oxygen, pairing of
D 5 ENERGY OF AN ELEMENT DECREASE down a group electrons in p-orbital occurs
IS THE ENERGY NEEDED for the first time-

This is because:

Document information

Uploaded on
June 28, 2026
Number of pages
2
Written in
2025/2026
Type
Lecture notes
Professor(s)
Pearson edexcel
Contains
All classes
£10.99
Get access to the full document:

Wrong document? Swap it for free Within 14 days of purchase and before downloading, you can choose a different document. You can simply spend the amount again.
Written by students who passed
Immediately available after payment
Read online or as PDF

Get to know the seller
Seller avatar
tealdisneymusic

Get to know the seller

Seller avatar
tealdisneymusic
View profile
Follow You need to be logged in order to follow users or courses
Sold
-
Member since
1 week
Number of followers
0
Documents
2
Last sold
-

0.0

0 reviews

5
0
4
0
3
0
2
0
1
0

Why students choose Stuvia

Created by fellow students, verified by reviews

Quality you can trust: written by students who passed their exams and reviewed by others who've used these revision notes.

Didn't get what you expected? Choose another document

No problem! You can straightaway pick a different document that better suits what you're after.

Pay as you like, start learning straight away

No subscription, no commitments. Pay the way you're used to via credit card and download your PDF document instantly.

Student with book image

“Bought, downloaded, and smashed it. It really can be that simple.”

Alisha Student

Working on your references?

Create accurate citations in APA, MLA and Harvard with our free citation generator.

Working on your references?

Frequently asked questions