Question

For each of the following ions, indicate the total number of protons and electrons in the ion. For the positive ions in the list, predict the formula of the simplest compound formed between each positive ion and the oxide ion. For the negative ions in the list, predict the formula of the simplest compound formed between each negative ion and the aluminum ion.a. Br-b. Ba+c. AlBr3

Answer 1

Explanation:

Atomic number is the sum of total number of protons present in an element. And, each element of the periodic table will have a different atomic number. Whereas atomic mass is defined as the sum of total number of protons and neutrons present in an atom.

Atomic number of bromine is 35 which means that it contains 35 protons and the number of neutrons present in it are as follows.

          atomic mass = no. of protons + no. of neutrons

                   80 = 35 + no. of neutrons

       no. of neutrons = 80 - 35

                                  = 45

In a neutral atom, the no. of protons is equal to the no. of electrons. As $Br^{-}$ has one negative charge which means that there are 36 electrons and 35 protons present in a $Br^{-}$ ion.

Atomic number of barium is 56 and no. of neutrons present in barium are as follows.

           atomic mass = no. of protons + no. of neutrons

                   137 = 56 + no. of neutrons

       no. of neutrons = 137 - 56

                                  = 81

As $Ba^{+}$ has one positive charge. So, it contains 55 electrons and 56 protons. Formula of its oxide is BaO

Atomic number of aluminium is 27 so, it has 27 protons. As $Al^{3+}$ has a 3+ charge so, the number of electrons present in it will be 25.