Calcium and potassium
Nitrogen and Phosphourus
The chemical properties of calcium are most similar to (in between) the chemical properties of magnesium and strontium.
Fluorine because it is in the same group (group 17) as Bromine therefore it has the same chemical properties
Elements in the same group are most similar.
Elements in the same family are related because of shared properties. For example, all the elements in the noble gas family do not react to anything and are colorless, nonflammable, odorless, and tasteless under normal circumstances.
elements in each group of the periodic table have identical chemical properties as they have the same no. of valence electrons which determines their chemical properties. since calcium is in group II of the periodic table, it has the same chemical properties as the elements in group II. Elements in group II consists of: Be, Mg, Ca, Sr, Ba, Ra Elements in the same group has different physical properties such as boiling and melting points. However there are trends of their physical properties down the group.
1 and 2
o, s, se
The chemical properties of calcium are most similar to (in between) the chemical properties of magnesium and strontium.
In the periodic table, the elements are grouped according to their properties. Elements in a group has an equal number of valence electrons. So the elements in a group have most common chemical properties.
Nitrogen is very similar in chemical properties to Carbon.
The most important principle was the listing in groups, after similar chemical or physical 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. But the other given elements do not lie in same group so they have different chemical properties.
Elements in the same group have similar electronic configurations. For example, all elements in Group 1 contain 1 unpaired electron located in an S orbital. It's the electronic configuration of atoms (and to a lesser degree, their size and charge) which dictate their chemical properties. Nuclear properties, on the other hand are dictated largely by the atoms size and number of protons and neutrons. Chemists, for the most part, aren't interested in these.
They have the same number of valence electrons which, in general, gives them similar oxidation numbers and other similar chemical and physical properties. The similarities are most pronounced in the groups at either side of the standard periodic table, and are least pronounced for the transition and rare earth elements.
number of valence electrons
There is no fully objective answer to this question. Many chemists would consider that two lanthanide elements with atomic numbers differing by only one would be likely to qualify. Another possibility is the pair zirconium and hafnium. These are very similar in most chemical characteristics but differ greatly in electron capture tendencies in nuclear reactors.
The most important is the electronegativity of chemical elements.