Q.3 A neutral atom has a mass number of 80 and has 45 neutrons. Write its complete symbol. Q.4 An atom has two more protons and two more electrons than the atom in question 3. What is its complete symbol?

Which of the following has 35 protons, 45 neutrons, and 35 electrons? Please look up the atomic number from the periodic table.

There are four isotopes of strontium. They have mass number of 84, 86,87 and 33. The atomic mass of strontium is 87.62 amu. What does it say about the relative abundance of isotopes?

Fill in the blanks. The positions of atoms on the periodic table of the ____ are determined by how many _____  are present in their nuclei; this also is called their atomic _____.  An atom's nucleus is made up of protons, which have _____ charges and ___ that do not have a ____charge.  The total of protons and neutrons in an atom defines its atomic ____ .  Two atoms with the same number of protons but different numbers of neutrons in their nuclei are considered _____ . The nucleus is surrounded by electrons, which have  charges.  Electrons are not found randomly, but occur in discrete _____ that are grouped into "shells".  The chemical properties of an atom, that is, the kinds of chemical reactions it has with other atoms or molecules, are determined by properties of its outermost set of orbitals, which is called its _____ shell.  Two atoms will react with each other if the reaction leads to a more stable state; specifically so that their valence shells are ____  .  The most common…