is calcium alkaline ???

The calcium is an alkaline earth metal . It is group II element in periodic table. Calcium is an electropositive metal . The valence electron of calcium is 2 . So it can donate two electrons easily . When calcium reacts with non metal electronegative element oxygen , it forms basic oxide . For this reason calcium is called alkaline earth metal .

Calcium and alkalinity .....

Trevor has correctly answer the question. Calcium is an "alkaline earth" metal. A "metal earth" is the metal oxide, for calcium, that is CaO, or lime. Lime reacts sparingly with water to produce a basic solution.

CaO + H2O <==> Ca(OH)2

Calcium hydroxide is a strong base, in that what little is dissolved is completely ionized.

Ca(OH)2(aq) --> Ca2+ + 2OH-

There terms "basic" and "alkaline" are related but not exactly the same. "Basic" and "basicity" refer to the presence and concentration, respectfully, of hydroxide ions. "Alkaline" and "alkalinity" refer to the ability to neutralize an acid. Therefore, "alkaline" refers to a broader group of substances, than simply the metal hydroxides. "Alkalinity" refers to the buffering capacity of a substance (and therefore, its ability to neutralize acids).

Calcium oxide -- CaO -- (an alkaline earth) is both basic (OH- ions are produced) and alkaline (neutralizes an acid).

Calcium hydroxide -- Ca(OH)2 -- is both basic and alkaline

Calcium metal, on the other hand is not alkaline, but it reacts with water and acids to produce Ca(OH)2 and salts which may result in basic solutions. For instance:

.... Ca(s) + 2HC2H3O2(aq) --> Ca(C2H3O2)2(aq) + H2(g)

.... C2H3O2^- + HOH(l) <==> HC2H3O2(aq) + OH-

This is why a solution of calcium acetate is basic.

Calcium metal is reactive enough to react with water

.... Ca(s) + 2HOH(l) --> Ca(OH)2(aq) + H2(g)

========== Follow up ==========

You wrote, " i think that calcium should be sweet because it causes the power in human body and i also think that scientist told lie that calcium is alkaline (bitter)."

You're not asking an actual chemistry question, and you aren't actually asking about elemental calcium. You're probably talking about the one of many ways to take extra dietary calcium. Most calcium which is taken for the benefit of your bones is in the form of a compound, the most common being calcium carbonate (CaCO3). Another is calcium citrate (Ca3(C6H5O7)2), the calcium salt of citric acid. There is even a supplement made from the calcium found in algae.

How any of these actually taste is up to the manufacturer and whatever flavors they add to their formulation.

when there is water around. Calcium will not create OH- ions without water being present first, but I would think that Calcium is located on the Periodic Table in the the chemical group Alkali Earth metals would give you the first indication that it is alkalic when the opportunity exists.

As an elemental metal , of Group 2, is described as 'Alkaline Earth Metal'.

Of its self it is not alkaline.

However, its compounds particularly the hydroxide are alkaline.

Calcium is a metal. It is neither acidic nor alkaline.

But - if the Ca metal is reacted with water , the following occurs

Ca+ 2H2O → Ca(OH)2 + H2

The Ca(OH)2 produced is sparingly soluble in water . But being a Gr11 metal hydroxide , it produces a basic or alkaline solution

I conclude

Calcium will produce alkaline hydroxides

Calcium as ca metal is not alkaline or acidic.

Yes. ..........................

Yes, calcium is alkaline. Calcium has a pH of between 10 and 12.5, which is very alkaline. The pH scale is 0-14 - 0 being extremely acidic (example: battery acid), 7 being neutral (example: pure water), and 14 being extremely alkaline (example: liquid drain cleaner).

Alkaline is also sometimes referred to as base or basic.