C2- The Periodic Table Flashcards
How did John Dalton arrange the elements on the periodic table in 1808?
In order of atomic mass
How did John Newlands arrange the elements on the periodic table in 1864?
In order of atomic mass and but started a new row every eight elements (law of octaves) as he notices the properties every eighth element was similar
Why did scientist not accept John Newlands’ ideas on the periodic table ?
- Because his law of octaves only worked up to calcium then broke apart
- some boxes had 2 elements in them
- he was not well-known/ respected scientist
How did Dimitri Mendeleev arrange the elements in the periodic table?
Arranged the 50 discovered elements in atomic mass but arranged them so that a periodic (regular occurring) pattern could be seen.
He left gaps
Why did Mendeleev leave gaps?
To make sure that elements with the same properties stayed in the same group, including the undiscovered ones
Whats did the discovery of the structure of the atom in the early 20th century show about the periodic table ?
That elements were in order of atomic (proton) number
What did the discovery of isotopes help explain about the periodic table?
The oddly heavy atomic mass of elements
Whats the max number of electrons in the first shell of an atom?
2 electrons
What do the number of electrons in an atoms outermost shell determine?
Its chemical properties
Whats does the group number tell us about the atoms structure?
The number of electrons its outer most shell
Do non metals gain or lose electrons
Gain
Do metals lose or gain electrons
Lose
Why are the noble gases (group 0) inert?
Don’t react with much as they have a full outermost shell
Periodic pattern
A regularly occurring pattern
What happens do the reactivity of the alkali metals (group1) as they go down the group?
Increases
What is produced when alkali metals react with water?
Hydrogen and an alkaline solution containing metal hydroxide
What is produced when alkali metals react with non metals?
Form 1+ ions to make ionic compounds
What is formed when alkali metals react with chlorine?
A salt
Describe the appearance of Fluorine
Pale yellow gas
Describe the appearance of chlorine
Pale green gas
Describe the appearance of Bromine
Red-brown liquid
Describe the appearance of Iodine
Grey solid or purple vapour
Which of the halogens is radioactive ?
Astatine
What ions are produced when halogens react with metals ?
Form 1- ions (called halides)
What happens when halogens react with non metals
Form covalent bonds (sharing electrons)
Whats the rule for displacement of halogens?
A more reactive halogen can displace a less reactive one from one of its salts
Which 3 factors decide how easy it is for atoms to gain or lose electrons?
- distance between outermost shell electrons and the nucleus
- the number of energy levels (shells) which provide protection
- the nuclear charge (this one is overweighted by the other 2 factors)
(Group1) the outer electron gets easier to _______ going down the group, and the elements become more reactive as the ______________________ due to the increased number of _______
Lose
Attraction from the nucleus is weak
Inner shells
Explain trend of electron attraction in halogens down the group
Going down the group its harder to gain an electron as the outermost shell’s electrons get further away from the attractive force of the nucleus
What happens to the reactivity of halogens (group 7)as you go down the group?
Decreases
Explain how the loss of electrons changes in Alkali metals going down the group?
The outer electron gets easier to remove going down the group as the attractive forces from the nucleus decreases the bigger the atom
