An element's most stable ion forms an ionic compound with chlorine, having the formula xcl2. if the ion of element x has a mass number of 40 and has 18 electrons, what is the identity of the element?

The unknown element X is calcium.

Explanation:

We are given:

An ionic compound having chemical formula =

The given compound is a neutral compound and in a neutral compound, the oxidation states are exchanged.

We know that:

Oxidation state of chlorine ion = -1

So, the oxidation state of X ion will be +2

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Number of electrons = Number of protons - charge

We are given:

Mass number = 40

Number of electrons = 18

So, number of protons = Number of electrons + Charge

Number of protons = 18 + 2 = 20 = Atomic number

Hence, the unknown element X is calcium having atomic number '20'

a. a clone will be physically identical to the original, but won’t be genetically identical

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each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i