Final answer:
In the compound 2Ca(OH)2, there are 4 calcium atoms, 4 oxygen atoms, and 4 hydrogen atoms.
Step-by-step explanation:
To determine how many atoms each element has in the compound 2Ca(OH)2, we analyze the chemical formula. This compound includes calcium (Ca), oxygen (O), and hydrogen (H). The formula indicates that there are two molecules of calcium hydroxide, Ca(OH)2. Thus, for calcium, there are 2 Ca atoms in one molecule, so in 2 molecules, there are 4 Ca atoms. Each molecule has two hydroxide (OH) groups, and since there is one oxygen and one hydrogen in one hydroxide group, each molecule contains 2 O atoms and 2 H atoms. Therefore, multiplying by 2 molecules, we have 4 O atoms and 4 H atoms.