Flashcards in chapter 2 Deck (13):
what is the periodic table
The periodic table is a method of organising all the known elements to show their similarities and differences.
historically how was the periodic table organised`
Historically, the development of the periodic table was based on the classification of elements according to their chemical and physical properties.
`what did Dmitri Mendeleev propose
Dmitri Mendeleev proposed that the properties of elements are a periodic function of atomic mass. He arranged the elements known at that time in a ‘periodic table’ with gaps for elements that he considered were yet to be discovered. His version of the table formed the basis of the modern periodic table that is widely used today.
what elements are radioactive and synthetic
Elements after uranium (atomic number 92) are artificially synthesised and radioactive. They are known as the transuranium elements.
how many elements are there to date
To date, elements up to 112 have been made, as well as elements 114 and 116; the last few elements are extremely unstable.
what do elements arranged down the same vertical columns (groups) in the modern periodic table display
Elements arranged down the same vertical columns (groups) in the modern periodic table display similar physical and chemical properties.
what do Elements arranged along the same horizontal rows (periods) are placed in order of increasing atomic number.
Elements arranged along the same horizontal rows (periods) are placed in order of increasing atomic number.
what are the three main features of the periodic table
– eight main groups, which progressively fill both the s and p subshells
– transition elements, which progressively fill the d subshells
– rare earth elements, which progressively fill the f subshells. Elements of the f block are made up of the lanthanoids and the actinoids.
modern periodic table fact
The fundamental structure of the periodic table as developed by Mendeleev has remained largely unchanged, despite the discoveries and developments of new theories of atomic structure.
where are metals most found
metals are mostly found on the left side and the middle of the periodic table, separated by the metalloids from the non-metals, which are found on the right.
what happens to the atomic size across the periods and groups
Atomic size decreases across the periodic table and increases down the groups.
what happens to electronegativity across a period and groups
Electronegativity generally increases across a period and decreases down a group.