C3 Periodic table etc Flashcards
In what order were the elements put in the early periodic table?
In order of increasing atomic weight. (now we call it atomic mass)
Write an ionic equation for the reaction of the alkali metal atom
Li → Li+ + e-
Na → Na+ + e-
K → K+ + e-
Rb → Rb+ + e-
Cs → Cs+ + e-
How were the elements put into columns or groups?
Elements with similar properties are in columns, known as groups.
Why was this known as a periodic table?
Periodic means repeats regularly, similar properties occur at regular intervals.
What were Newlands’ octaves?
John Newlands published a table showing that every eighth element had similar properties and could be grouped together.
State the two main problems with the early periodic tables.
They were incomplete, only 56 elements had been found by 1865 for Newlands to octave.The elements were arranged by mass or weight which meant that some atoms did not fit the pattern and were put in the wrong groups.
How did Mendeleev overcome problems with the early periodic tables?
When he made his table, Mendeleev left spaces for elements that were yet to be discovered, famously Ga and Ge, so that the other elements fitted into the right groups.
What did Mendeleev use to sort the elements into groups in his periodic table in 1869?
The elements were still in order of atomic weight. They were put into groups using their properties and the formulae of their compounds.
Explain why scientists thought the periodic table of the elements was a curiosity at first?
The early tables were incomplete, some only worked for the first few elements.
What discovery led to the modern versions of the periodic table?
The discovery of electrons, protons and neutrons early in the twentieth century.
In what order were the elements put in the modern periodic table?
In order of increasing atomic number.
What difference did this make to the modern periodic table?
The elements were placed in the proper groups.
How does this change to the order of the elements link to atomic structure?
The periodic table could be used to work out the electronic structure of the elements as well as the number of protons and neutrons.
How does the electronic structure change across each period in the table?
In period 1 the first shell is filled, in the second period the second shell is filled, etc. e.g. Li- 2.1, Be- 2.2, B- 2.3, C- 2.4.
How does the electronic structure change down each group in the table?
Elements in the same group have the same number of electrons in their highest occupied electron shell (outer shell).