The Modern periodic table
Scientists continued to revise Mendeleev鈥檚 periodic table.
- The Modern periodic table is arranged in order of increasing The number of protons in the nucleus of an atom. Also called the proton number., rather than atomic weight.
- there are now over 100 elements and no gaps in the periodic table.
- a group of unreactive elements 鈥 the The elements in Group 0 of the Periodic Table, named for their lack of chemical reactivity. 鈥 were discovered at the end of the 1800s.
- the modern periodic table includes actinides and lanthanides.
The Modern periodic table
Groups and periods
The modern table is called a 鈥減eriodic鈥 table because the elements with similar properties appear at regular intervals.
- the vertical columns are called A vertical column in the periodic table containing elements with similar chemical properties.
- the horizontal rows are called A period is a horizontal row in the periodic table.