Because no two elements are exactly alike. For instance, gold and silver may both be in the transition metal group and have similar properties like rust resistance and conductivity, but they have different melting points (gold 1356 kelvin, silver 1241 kelvin) for instance.
They are different elements. However, most of their chemical properties are similar, because of the similar numbers of electrons in their valence shells. Their physical properties differ because of the mass contained in the atoms of each element.
Elements in a group have the same number of valence electrons. Hence they have similar properties. However the total number of protons / electrons is different for the elements. hence they do not have identical properties.
Element within a group have nuclei of different sizes so that their valency electrons are at different distances from the nuclei. This affects their electronegativity and thence other chemical properties.
They do, have similar properties. Any elements in the same group have the same properties.
They have different numbers of nonvalance electrons
Silicon, carbon's only neighbor within its periodic table column 14.
They have different numbers of valance electrons...
Dobereiner is remembered for what were called "Dobereiner's Triads" which are groups of three elements having similar chemical properties. This is a forerunner of the periodic table, but it is not actually a table, and it does not offer any explanation for the chemical similarities observed within the triads. Mendeleev's Periodic Table of the Elements shows the relationship of every element to every other element, and explains why they all have the chemical properties that they have.
The groups in the periodic table tell you what each element within them will react with, the number of valance electrons the element has, and what family it is in.
They have different numbers of valance electrons...
Elements present within a same group normally have similar properties
Elements in group A are metals. They possess metallic behaviour.
Elements in group A are metals. They possess metallic behaviour.
Elements in group A are metals. They possess metallic behaviour.
Silicon, carbon's only neighbor within its periodic table column 14.
Element within a group have nuclei of different sizes so that their valency electrons are at different distances from the nuclei. This affects their electronegativity and thence other chemical properties.
They have different numbers of valance electrons...
To find an element that is similar to another element, look in the periodic table and find an element in the same column (group/family) as the element of interest. Usually, elements within the same group/family have very similar properties.
Dobereiner is remembered for what were called "Dobereiner's Triads" which are groups of three elements having similar chemical properties. This is a forerunner of the periodic table, but it is not actually a table, and it does not offer any explanation for the chemical similarities observed within the triads. Mendeleev's Periodic Table of the Elements shows the relationship of every element to every other element, and explains why they all have the chemical properties that they have.
The groups in the periodic table tell you what each element within them will react with, the number of valance electrons the element has, and what family it is in.
The periodic trends that arise from the arrangement of the periodic table provide chemists with an invaluable tool to quickly predict an element's properties. These trends exist because of the similar atomic structure of the elements within their respective group families or period and the periodic nature of the elements.
Beryllium, Calcium or any other element within the same family or group (vertical column on the periodic table)