Module 1

Created by

Tianna

Cards (16)

Mass number 
the number of protons plus neutrons in the nucleus of an atom
isotopes 
atoms with the same atomic number/number of protons but different number of neutrons therefore different mass numbers.
Relative atomic mass 
the mass of one atom of an element relative to the mass of one atom of the carbon-12 isotope
Relative isotopic mass 
the mass of an atom of a specific isotope of the element relative to the mass of the standard carbon-12 isotope.
Radioactivity 
A radioactive isotope has nuclei which undergo spontaneous disintegration producing electromagnetic radiation in an attempt by the atom to attain nuclear stability.
Alpha Decay 
Occurs in isotopes which are unstable because their nuclei are too heavy.
Beta Decay 
Occurs in nuclei with an n/p ratio above the stable value
Gamma Decay/ Electron Capture 
When isotope have a n/p ratio below the stable value. The nucleus captures an electron from its innermost shell, this combines with a proton to form a neutron
Isotopic Decay
Uses of radioistopes 
R
Atomic Orbitals 
A region of space where there is a high probability of finding an electron.
state the factors that influence first ionisation energy
Atomic radii, nuclear charge, shielding
Size of nuclear charge
As the distance increases, the attraction of the positive nucleus for the negative electron decreases and the ionization energy decreases.
Atomic radii 
As the nuclear charge becomes more positive with increasing proton number, its attraction for the increases and consequently the ionization energy increases.
*NB - increasing atomic radii and shielding outweighs the increasing nuclear charge.
Describe the structure of an atom
A
Shielding 
Electrons in the inner shells exert a repelling effect on electrons in the outermost shell of an atom, this is screening/shielding.
This screening effect means that effective nuclear effective nuclear charge is much less than the full positive charge in the nucleus.