What are the 18 columns of the periodic table called?
The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.
Why are there only 18 groups in the periodic table?
The idea behind the periodic system is to find regularities (hence the name) between elements. It turns out, that individual groups and trends within them are similar in the 8 “main” groups (as you have learned). Hence, one could justify up to 32 groups, but for practical reasons, 18 are conventionally used.
Do groups have similar properties?
Elements in the same group have similar properties because they have the same number of valence electrons in their outermost shell. Elements in the same period have different properties because the number of valence electrons in their outermost shells differ.
Why do same groups have similar properties?
(a) (i) All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell. (ii) All the elements of a period have different chemical properties because they have different no.
Do elements in same group have same physical properties?
A vertical column in the periodic table of elements is called group. So, we can say that elements in a group have the same physical and chemical properties because their atoms have the same number of valence electrons or same valence shell electronic configuration.
Which elements have similar physical properties?
Explain your answer. Sodium and potassium share similar physical and chemical properties because they are in the same family or group called Alkali metals. Both will have the same valence electrons and they are both very reactive. Bohr Models: For each element, write down the number of protons, neutrons and electrons.
What do the periods have in common?
All of the elements in a period have the same number of atomic orbitals. For example, every element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons.
Which metal is the most reactive and why?
cesium