L7 - The Periodic Table

• Chemistry
• Secondary Education

Lesson 1 - What is IGCSE Chemistry?

4

10

Today, I'm going to...

• know about the Periodic Table,
• be able to explain how the position of an element in the Periodic Table can be used to predict its properties, and
• understand why the elements are arranged the way they are.

• I can define what a proton is.
• I can describe how the elements in the Periodic Table are arranged.
• I can define what metallic character means.
• I can identify patterns across periods of metallic to nonmetallic character.

I am successful if...

Experimental Design

Write a hypothesis.

Observe and ask a question.

Carry out the experimental plan. 

Plan an experiment to test your hypothesis.

 Evaluate and interpret experimental methods.

Interpret and evaluate experimental data.

Why could it be included in Group I?

Why could it be included in Group I?

Why could it NOT be included in Group I?

2, 1

2, 8, 1

2, 8, 8, 1

2, 8, 18, 8, 1

Periodic Table

similarities between their properties

PAST: based on atomic masses

PRESENT: based on atomic number

Dmitri Mendeleev

Mendeleev was the first to publish a version of the table that we would recognise today, but does he deserve all the credit?

Antoine Lavoisier

• 1789 - earliest attempt to classify the elements 
• grouped the elements based on their properties into gases, non-metals, metals and earths

Johann Döbereiner

• 1829 - triads of elements with chemically similar properties, such as lithium, sodium and potassium
• the properties of the middle element could be predicted from the properties of the other two

Alexandre Béguyer de Chancourtois 

• 1862 - a geologist, principal contribution to chemistry was the 'vis tellurique' (telluric screw), a three-dimensional arrangement of the elements constituting an early form of the periodic classification
• The telluric screw plotted the atomic weights of the elements on the outside of a cylinder, so that one complete turn corresponded to an atomic weight increase of 16
•  the first to use a periodic arrangement of all of the known elements, showing that similar elements appear at periodic atom weights

John Newlands

• noticed that there were similarities between elements with atomic weights that differed by seven (The Law of Octaves, drawing a comparison with the octaves of music)
• there was a periodicity of 7 and not 8 in the Newlands table
• discoverer of the Periodic Law of chemical elements

Julius Lothar Meyer 

• produced several Periodic Tables between 1864-1870
• four years older than Mendeleev
• the first table contained just 28 elements, organised by their valency (how many other atoms they can combine with)
• in 1868 he incorporated the transition metals in a much more developed table
• 1868 table listed the elements in order of atomic weight, with elements with the same valency arranged in vertical lines, strikingly similar to Mendeleev’s table
• his work wasn’t published until 1870, a year after Mendeleev’s periodic table had been published

• after 1870, Meyer and Mendeleev were still unaware of each other’s work, although Meyer later admitted that Mendeleev had published his version first
  
• the first person to recognise the periodic trends in the properties of elements, and the graph shows the pattern he saw in the atomic volume of an element plotted against its atomic weight

The Development of the Periodic Table

Dmitri Mendeleev

• discovered the periodic table (or Periodic System, as he called it) while attempting to organise the elements in February of 1869
• by writing the properties of the elements on pieces of card and arranging and rearranging them until he realised that, by putting them in order of increasing atomic weight, certain types of element regularly occurred
• real genius of Mendeleev’s achievement was to leave gaps for undiscovered elements
• Scandium and Germanium were the other two elements discovered by 1886, and helped to cement the reputation of Mendeleev’s periodic table.

Arrange the cards

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The Periodic Table is a way of arranging the elements according to their properties. They are arranged in order of their _____ number.

1. atomic
2. proton
3. mass
4. A or B

Elements with similar properties are placed together in _________.  __________ called _____________.

Periods are ___________ __________ of the elements.

horizontal rows

vertical columns

diagonal lines

The table shows trends down the ___________ and patterns across the _______________.

1. groups, periods
2. periods, groups
3. weight, lines

• Where are the metals located? 
  
• Where are the non-metals located? 
• Do you see any trend or pattern regarding the metallic properties of the elements?

Think about these

Choose the odd-one-out:

SET 1 - sodium, magnesium, aluminium, silicon, phosphorus

SET 2 - potassium, chromium, cobalt, germanium, bromine

3Os: Odd-One-Out

Arrange the given elements according to their metallic property. 

(a) more metallic to less metallic character

• Zirconium, Tin, Rubidium, Silver, Rhodium

(b) non-metallic to metallic character

• Magnesium, Silicon, Sulfur, Sodium, Chlorine, Phosphorus

Metal or non-metal?

If you could change anything in the Periodic Table, what would you change? Explain why.