1. Al(C₂H₅)₂OCl₃
Al(C₂H₅)₂OCl₃ is made from 5 different elements. They are Al, C, H, O and Cl. Number of atoms in each element can be found as follows.
number of Al atoms = 1
number of C atoms = 2 x 2 = 4
number of H atoms = 5 x 2 = 10
number of O atoms = 1
number of Cl atoms = 3
Total number of atoms = 1 + 4 + 10 + 1 + 3 = 19
2. BCl₃
BCl₃ is a simple neutral molecule. It consists of 2 different elements as B and Cl. Total number of atoms is 4. Number of atoms can be calculated as follows.
number of B atoms = 1
number of Cl atoms = 3
Total number of atoms = 1 + 3 = 4
3. H₂O + H⁺
H₂O makes H₃O⁺ (hydronium ion) with H⁺ which is a positive ion. H₃O⁺ consists of two different elements as H and O. Number of atoms are as follows.
number of H atoms = 3
number of O atoms = 1
Total number of atoms = 3 + 1 = 4