Periodicity Flashcards
Define “Ionisation Energy” and its use
the minimum energy required to remove the most loosely bound or outermost electron from a gaseous atom in its ground state
- useful for determining the properties of the element
- indicator for the strength of the force operating between the nucleus and the electrons
What affects the magnitude of ionisation energy?
- the distance of the electrons from the nucleus
the size of the nuclear charge - the presence of inner shells (shielding)
What is the equipment used to remove an electron?
a discharge tube where the electrons always move away from the cathode.
- the electron from the cathode strikes a gaseous atom X and ionises it, and an electron is removed from X and a gaseous ion is formed
How many ionisation energies would an electron with n electrons have?
n amount
Why does it take more energy to remove an electron in each successive ionisation energy?
it is harder to remove an electron from a positive ion compared to a neutral atom because the electron has more electrostatic attraction and less electron repulsion.
What happens if there is a massive jump in ionisation energy?
- a cation is removing an electron from a different and stable shell
- successive elements where the noble electron configuration with a full shell requires a lot of ionisation energy
Which atoms would be located at the peaks (for ionisation energy)
noble or group 7 gases
Which atoms would be located at the troughs (for ionisation energy)
group 1 and group 2 metals
How does ionisation energy increase?
increase across a period
decrease down a group
Why would oxygen have a lower ionisation than nitrogen and sulfur less than phosphorous?
both nitrogen and phosphorous have half-filled p orbitals, which is a stable configuration.
Are the reactivities or metal consitent with the ionisation values>
No, because reactivities depend on how metals react with water and acids, as well as how the metals are packed in their lattices, and the energy required to disrupt the lattice.
What are the representative elements?
The elements of the main block, Group I - VIII
What are the two types of radioactive elements?
synthetic and natural
What is the significance of elements in the same group?
- they have similar chemical properties as they will lose or gain the same number of electrons
- this is so that they can attain a noble gas configuration
Define “electronegativity”?
- a measure of the electron attracting power of an atom in a molecule
- determined using the Pauling scale
Define “metallic character”
having the physical properties which are usually attributed to metals:
- ductility
- malleability
- hardness
- ability to conduct electricity and heat well
Define “non-metallic character”
having the physical properties which are attributed to non-metals:
- being brittle
- poor conductor of heat and electricity
Define “chemical reactivity”
the tendency to form compounds and the rate at which this occurs
Define “electron affinity”
a measure of the energy released when one electron is added to an atom of an element
Why is there a change from non-metallic to metallic properties as a group descends?
increase in shell number means that the valence electrons are located further from the nucleus and therefore more easily lost by atoms