The two rows of 14 elements at the bottom of the periodic table are the lanthanides and the actinides, whose positions in the periodic table are indicated in group 3.
The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass. The rows are called periods.
Is K an alkali metal?
Group 1A (or IA) of the periodic table are the alkali metals: hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These are (except for hydrogen) soft, shiny, low-melting, highly reactive metals, which tarnish when exposed to air.
Which best describes how the current periodic table is arranged?
In the modern periodic table, the elements are arranged according to their atomic number – not their relative atomic mass . In the periodic table the elements are arranged into: rows, called periods , in order of increasing atomic number. vertical columns, called groups , where the elements have similar properties.
What are 3 elements that have similar properties?
Magnesium, strontium, and barium belong to group 2A of the periodic table. These have two valence electrons in their outermost shell. So these three elements have similar chemical properties.
Why are actinides called actinides?
Actinides are the 15 elements with atomic numbers from 89 to 103. They are named after the first element in the series, actinium. … The actinides are most known for the elements uranium and plutonium which are used in nuclear reactors and nuclear bombs.
Why are there 14 lanthanides and actinides?
There are 14 lanthanides and actinides because the differentiating electron enters (n – 2)f subshell. Here the maximum capacity of f sunshell is 14 electrons. Therefore, there are only 14 lanthanides and 14 actinides.