The Periodic Tabel

Question 1

What did Newlands and then Mendeleev?

Answer 1

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, know as groups. The table is called a periodic table because similar properties occur at regular intervals.

Question 2

Describe the early periodic table and how its problems were overcame

Answer 2

The early periodic tables were incomplete and some elements were placed in inappropriate and some elements were placed in inappropriate groups if the strict order of atomic weights was followed.
Mendeleev overcame some of the problems by leaving gaps for elements that he thought had not been discovered

Question 3

When were electrons, protons and neutrons discovered?

Answer 3

In the early 20th century, the periodic table was arranged in order of atomic (proton) numbers. When this was done, all elements were placed in appropriate groups

Question 4

Describe the modern periodic table

Answer 4

The periodic table can be seen as an arrangement of the elements in terms of their electronic structures. Elements in the same number of electrons in their highest occupied energy level (outer shell)

Question 5

What is Group 1 called?

Answer 5

Alkali metals

Question 6

Describe the alkali metals

Answer 6

They are metals with low density (the first three elements in the group are less dense0
React with nonmetals to form ionic compounds in which the metal ion carries a charge of +1. The compounds are white solids that dissolve in water to form colourless solutions
react with water, releasing hydrogen
from hydroxides that dissolve in water to give alkaline solutions

Question 7

In Group 1, the further down the group an element is:

Answer 7

the more reactive the element

The lower its melting point and boiling point

Question 8

Compared with the elements in Group one, transition elements:

Answer 8

Have higher melting points (except for mercury) and higher density
Are stronger and harder
Are much less reactive and so do reactive and so do not react as vigorously with water or oxygen

Question 9

What do many transitions elements have?

Answer 9

Many have ions with different charges, formed coloured compounds and are useful as catalysts

Question 10

The elements in Group 7 of the periodic table react with metals to form:

Answer 10

ionic compounds in which the halide ion carries a charge of -1

Question 11

In Group 7, the further down the group an element is:

Answer 11

The less reactive the element

The higher its melting point and boiling point

Question 12

A more relative halogen can ….. a less reactive halogen from an ….. solution of its …

Answer 12

displace
aqueous
salt

Question 13

The trends in reactivity within groups in the periodic table can be explained because:

Answer 13

the higher energy level of the outer electrons
the more easily electrons are lost
the less easily electrons are gained