Periodicity Flashcards
Why is the periodic table ‘periodic’ ?
The table is ‘periodic’ because elements with similar properties occur at regular intervals, i.e. periodically.
What was the first ever periodic table ? Who made it and what properties was it ranked by ?
John Newlands was the first chemist to devise a periodic table.
His periodic table was ordered by the weight of the element.
However, the table was incomplete, and some elements were placed in inappropriate groups.
How did mendeleev add to Newlands periodic table ?
Dmitri Mendeleev realised that there may be undiscovered elements.He added gaps to Newlands’ table to account for undiscovered elements.He even predicted the properties and masses of these undiscovered elements!
How is the modern periodic table similar to mendeleevs table ?
The discovery of protons and isotopes has shown that Mendeleev ordered elements exactly by atomic number (number of protons).Therefore, the modern periodic table looks very similar to Mendeleev’s (except the gaps are filled
Property of metals to note
Metals are all solids (except for mercury) at room temperature.
Why are non metals on the right hand side of the periodic table ?
Non-metals are found on the right of the periodic table because they have many electrons in their outer shell.
Why is there a certain order electron shells are filled ? Smallest to biggest distance from the nucleus.
Electrons fill an atom’s shells in order of increasing energy.
The closer a shell is to the nucleus, the lower its energy level, so the first shell that is filled is the closest to the nucleus.
