When beryllium ion combines with carbonate ion, the numbers of each ion are? ?

One of each

Explanation:

Be is in Group 2, so it loses its two valence electrons in a reaction to form Be²⁺ ions.

Carbonate ion has the formula CO₃²⁻.

We can use the criss-cross method to work out the formula of beryllium carbonate.  

The steps are

Write the symbols of the anion and cation.

Criss-cross the numbers of the charges to become the subscripts of the other ion.

Write the formula with the new subscripts.

Divide the subscripts by their highest common factor.

Omit all subscripts that are 1.

When you use this method with Be²⁺ and CO₃²⁻, you might  be tempted to write the formula for the beryllium carbonate as Be₂(CO₃)₂

However, you can divide the subscripts by their largest common factor (2).

This gives you the formula Be₁(CO₃)₁.

We omit subscripts that are 1, so the correct formula is  

BeCO₃

There is one Be²⁺ ion and one CO₃²⁻ ion in a formula unit of beryllium carbonate.

answer: c.

explanation:

the temperature of the gas, in k, not celsius.