Chemistry Unit 3.1 - The Periodic Table

HideShow resource information
How did Newlands, and Mendeleev attempt to classify elements?
They attempted to classify the elements by arranging them in order of their atomic weights. The list can be arranged in a table so that elements with similar properties are in columns, known as groups.
1 of 12
Why is it called a periodic table?
Because similar properties occur at regular intervals.
2 of 12
Who proposed the Law of Octaves? And what is it?
Newlands spotted a pattern where properties of elements seemed to repeat themselves every eighth element.
3 of 12
Why was Newlands table not accepted?
There were many inconsistancies in Newlands' ideas about similar properties so they weren't as quickly accepted, his ideas only work for around the first twenty elements. Newlands had missed the noble gases from the model.
4 of 12
How did Mendeleev's model differ from Newlands?
Mendeleev predicted properties of the other elements, unlike Newlands. People were conviced by Mendeleev's table's use when his predictions to the missing elements proved correct.
5 of 12
What was discovered in the 20th Centruy, and how did this affect the table?
When electrons, protons and neutrons were discovered early in the 20th century, the periodic table was arranged in order of atomic (proton) numbers. When this was done, all elements were placed in appropriate groups.
6 of 12
Describe alkali metals.
Low density. React with non-metals to form ionic compounds in which the metal ion carries a charge of +1.
7 of 12
Describe alkali metals ...(cont.)
React with water, releasing hydrogen to form hydroxides that dissolve in water to give alkaline solutions. Further down, low b/m points.
8 of 12
Compare transition elements to alkali metals.
Have higher melting points (except for mercury) and higher densities. Are stronger and harder. Are much less reactive and so do not react as vigorously with water or oxygen.
9 of 12
Describe halogens (group 7).
Form coloured vapours. Consist of molecules which are made up of pairs of atoms. Form molecular compounds with other non-metallic elements 4.Form ionic salts with metals in which the chloride, bromide or iodide (Halide Ion) carries a charge of -1.
10 of 12
Describe halogens (group 7)...cont
The Reactivity DECREASES as we go down group 7... As we go down the group each element has an extra full shell of electrons. These full shells shield the outer shell from the positive nucleus. This makes it more difficult to gain new electron. H m/b
11 of 12
Describe reacting of halogens.
A more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt.
12 of 12

Other cards in this set

Card 2

Front

Why is it called a periodic table?

Back

Because similar properties occur at regular intervals.

Card 3

Front

Who proposed the Law of Octaves? And what is it?

Back

Preview of the front of card 3

Card 4

Front

Why was Newlands table not accepted?

Back

Preview of the front of card 4

Card 5

Front

How did Mendeleev's model differ from Newlands?

Back

Preview of the front of card 5
View more cards

Comments

adamjeffries

Very useful

Similar Chemistry resources:

See all Chemistry resources »See all The Periodic Table resources »