Topic C1-atomic structure and the periodic table Flashcards
What are elements?
Is a substance made up of atoms that all have the same number of protons in there nucleus
What is the radius of an Atoms?
0.1 nanometers this is - (1✖️10🔛🔝-10)
What is the radius of the nucleas ?
1✖️10🔛🔝-14
What is the mass of the Electrons ?
It has no mass
What are Isotopes?
They are different forms of the same element which have the same number of protons but a different number of neutrons
What are compounds?
Are substances formed from two or more elements, the atoms of each are in a fixed proportions throughout the compound and they are held together by chemical bonds
What is the history of the atom
At the start of the 19 century John Dalton described atoms as solid spheres and said that different spheres make different elements
Then in 1897 J J Thomson said that atoms were “not solid spheres” his experiment concluded that atoms must contain even smaller negatively charged particles= Electrons. This theory was know as the “Plum Pudding Model”
Later in 1909 Rutherford did his famous alpha particle scattering experiment.This is where they fired positively charged particles at a sheet of gold. He said that there was a positively charged Nucleus surrounded by a “cloud” of negative electrons.
Next Bohrs nuclear model said that the electrons were placed in a shell at a set distance away from nuclear
And finely they found that protons existed
What are the properties of metals?
Strong but can be bent into different shapes this means it is it is malleable
Great at conducting heat and electricity
High melting and boiling
What are the properties of nonmetals?
Dull looking
More brittle
Do not conduct electricity
Low density
What are the properties of group 1 elements ?
All soft
Have low density
That trends do alkali metals have as they go down the group?
Increasing reactivity- easer to lose the outer electron because the attraction between the nucleus is weeker as more shells are added
Lower melting and boiling points
Higher relative atomic mass
What is the reaction between water and group 1 metals
They react very vigourously
They become more reactive as they go down the group
Lithium, sodium and potassium flowed and move around the surface fizzing furiously
They produce hydroxide + hydrogen
What do you all group 7 elements exist as
Diatomic elements
What trends happen as you go down group 7
Become less reactive-it’s harder to gain an extra electron because the outer shell is further from the nucleus
Have higher melting and boiling points
Have a higher relative atomic mass
