2.1 - Atomic structure and isotopes Flashcards
What has virtually the same mass as a proton?
A neutron
What has negligible mass?
An electron - about 1/1836th that of a proton
What is the charge of proton, neutron, electron
Positive
Neutral - no charge
Negative
What is the actual charge on a proton?
+1.60217733 x 10^-19 C
info about atom
- nearly all of an atoms mass is in the nucleus
- atoms contain same number of protons as electrons
What can neutrons be thought of as?
They can be thought of as providing the glue that holds nucleus together despite electrostatic repulsion between its positively charged protons
As the nucleus gets larger, what is needed?
More and more neutrons are needed
Every atom of the same element contains same number of …
Every atom of the same element contains same number of … protons!
Different elements contains atoms that have different numbers of …
Different elements contains atoms that have different numbers of … protons
What does the atomic number show?
The number of protons in the atom
What are isotopes?
Atoms of the same element with different numbers of neutrons and different masses
-most elements are made up of a mixture of isotopes
How are isotopes represented?
16 (Mass number A)
O
8 (atomic number Z)
What are other ways of representing isotopes?
An isotope may be written as
16
O
or oxygen-16
All oxygen atoms contain 8 protons, so if ‘8’ is omitted you still know how many protons each isotope contains
What do chemical reactions involve?
They involve the electrons surrounding the nucleus:
- different isotopes of same element have same number of electrons
- the number of neutrons has no effect on reactions of an element
- different isotopes of an element therefore react in same way
What small differences in physical properties will isotopes of an element have?
Higher melting point / boiling point / density (for higher-mass isotopes) + slower rates of diffusion
