C3 = The Periodic Table Flashcards
Why was Newlands’ discovery not accepted by scientists?
After calcium the properties didn’t match up well, he didn’t take into account that we hadn’t found all the elements, we probably still haven’t
Who came up with a new periodic table that was more accepted than Newlands? And why?
Mendeleev
He left gaps where new elements could be discovered and predicted the elements before they were found, when they were and matched his description, scientists believed him. He provided the basis for the modern periodic table.
What orders the modern periodic table?
The atomic (proton) number
Why do the properties match down the groups?
Because they have the same number of electrons on the highest energy level
How does the reactivity change within different groups of the periodic table?
With metals reactivity increases going down the group
With non-metals reactivity decreases going down a group
Why?
Going down the group there are more energy levels, so the electrons are less attached to the nucleus. In metals, they lose electrons so as one goes it gets closer to the nucleus and reactivity increases, in non metals the electrons just add up and grow further and further from the nucleus.
Why are group one called the alkali metals?
They are all metals that react readily with air and water.
Give 4 properties of alkali metals
Low melting and boiling points
Low density
React with water to produce hydrogen and an alkaline solution containing the metal hydroxide
All have one electron in their outer shell, so react with group 7 halogens and become 1+
Give 4 properties of transition metals
High melting and boiling points
Malleable and ductile
Good conductors of heat and electricity
Brightly coloured
Are the halogens in group 7 metals?
Non metallic
When a halogen reacts with a metal what charge is formed?
Charge of 1- because it needs one electron to reach it’s full outer shell
What did Newlands discover?
That if he put the elements in atomic weight, rows of 8 the properties would match up
