The periodic table and energy Flashcards
What is the first ionisation energy
The energy taken to remove an electron from the outer shell of 1 mole of gaseous atoms and turn them to one mole of gaseous 1+ ions
What are the factors that influence ionisation energy?
- Atomic radius
the larger the radius the smaller the nuclear attraction - Nuclear charge
the higher the nuclear charge the larger the attractive force - Electronic shielding
inner shells repel outer shells as they are all negative, the more inner shields the smaller the nuclear attraction
Describe the trends across a period
the number of protons in nucleus increase so their is a higher attraction on the electrons
electrons added to the same shell so outer shell is drawn inwards this decreases the atomic radii
the same number of inner shells = electronic shielding not changing
- attraction between nucleus and outer electrons increase so more energy is needed to move an electron this increases the 1st ionisation energy
describe trends down a group
number of shells increase so the distance from the outer electrons from the nucleus so weaker attraction force on electrons
more inner shells this increases shielding therefore weaker attraction
atomic radius increases
- number of protons also increased but this is outweighed by the other factors therefore decreases in 1st ionisation energy
Why is there a decrease in ionisation energy between groups 2-13? Be and B
group 13 has outermost electron in p-orbital whereas group 2 has outermost electron in s-orbital, p-orbitals have higher energy so are further away from nucleus so easier to move this decreases 1st ionisation energy
Why is there a decrease between groups 15-16? N and O
group 16 has paired electrons in outermost shell therefore experiences repulsion and is easier to get rid of as it has a lower 1st ionisation energy
What is the quantum number used to describe?
they are used to describe the electrons in atoms
The number representing the relative overall energy of each orbital which increases with distance from the nucleus
What are the different types of orbitals?
s
p
d
f
What is the shape of an s-orbital?
sphere
How many electrons can a p-orbital hold?
3
Why are the arrows going the opposite way when drawing an electron?
they have opposite spins
How many electrons can a s orbital hold?
2
What did aristole believe
He believed that the world was made out of 4 elements, earth, air, fire and water. this is similar to the states that we have today - solid liquid air and fire (plasma)
What did scientists begin to understand about the elements
noticed that some elements could be more easily extracted such as gold as they were found in their native state
what year and what did Antoine-Laurent de Lavoisier produce
1789 he produced the first chemical textbook
What was in Antoine-Laurent de Lavoisier’s book
complied list of elements that he believed could not be broken down any further
What was the strengths and Weaknesses of Antoine-Laurent de Lavoisier’s periodic table
+ showed a difference between metals and non-metals
- included some compounds and mixtures
- included terms such as light and heat
What did Jöns Jakob Berzelius produce and when
in 1828 he published a table of atomic weights and determined the mass of many compounds
What did Jöns Jakob Berzelius introduce
letter base symbols
What did Johann Wolfgang Döbereiner come up with
he noticed that certain groups of three elements called triads ordered by atomic weight would have a middle element with a weight and two properties that were roughly an average of the other two elements for example
- calcium, strontium and barium
- chlorine, bromine and iodine
- lithium, sodium and potassium
What did John Newlands do
arranged the table in order of relative atomic weights and in 1865 he suggested the law of octaves
What were the limitations of John Newlands table
- many elements were not known about
- left no gaps for undiscovered elements
- mixed metals and non-metals
- order periods down the table and groups across