Summary
Summary Chemistry Unit 1 Definitions
- Course
- Institution
This is a document featuring definitions for the key words for Chemistry Unit 1.
[Show more]
Seller
Follow
jasonsenoo
Content preview
Topic 1.5 Atomic structure and the periodic tableDefinitions
Nucleus
A dense region at the core of the atom which contains most of the mass of the atom
Proton
A positively charged fundamental particle (relative mass = 1, relative charge = +1) found in the nuclei of atoms
Neutron
An uncharged fundamental particle (relative mass = 1, relative charge = 0) found in the nuclei of atoms
Electron
A negatively charged fundamental particle (relative mass = 1/1840, relative charge = -1) found outside the nuclei of atoms
Atomic number
The number of protons in the nucleus of an atom
Mass number
The total number of protons and neutrons in the nucleus of an atom
Isotope
Isotopes are atoms of the same element which have the same number of protons but different numbers of neutrons
Isotopes of an element have the same atomic number but a different mass number
Nuclide
A nucleus with a specified number of protons and neutrons
Relative isotopic mass
The relative isotopic mass is the mass of one atom of that isotope divided by one twelfth of the mass of one atom of
carbon-12 ( 126 C )
Relative atomic mass (Ar)
The relative atomic mass of an element is the weighted average mass of atoms of that element divided by one twelfth of the
mass of one atom of carbon-12
Relative formula mass (Mr)
The sum of the relative atomic masses of all the atoms in the formula of a substance
Relative molecular mass (Mr)
The sum of the relative atomic masses of all the atoms in one molecule of a substance
First ionisation energy (enthalpy) (∆HIE1)
The enthalpy change (endothermic) when one mole of electrons is removed from one mole of atoms in the gas phase to
form one mole of singly charged positive ions
M(g) → M+(g) + e-
Second ionisation energy (enthalpy) (∆HIE2)
The enthalpy change (endothermic) when one mole of electrons is removed from one mole of singly charged positive ions in
the gas phase to form one mole of doubly charged positive ions
M+ (g) → M2+(g) + e-
Atomic orbital
A region of space within an atom which may be occupied by up to two electrons
s-block
The section of the periodic table in which atoms of the elements have their highest energy electron(s) in an s-subshell
p-block
The section of the periodic table in which atoms of the elements have their highest energy electron(s) in a p-subshell
i.e. Groups III to VIII (or 0)
d-block
The section of the periodic table in which atoms of the elements have their highest energy electron(s) in a d-subshell
02/06/2009
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller jasonsenoo. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.67. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
62890 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now