Multiple ChoiceWhich of the following is the number of protons in an atom of the element with atomic number 13?55views
Multiple ChoiceWhich of the following is the smallest chemical unit that retains the properties of a pure substance?57views
Multiple ChoiceAn atom contains 11 protons and 12 neutrons. What are its atomic number and mass number?60views
Multiple ChoiceWhich of the following is the major impurity added to silicon to create n-type semiconductors?36views
Multiple ChoiceHow many neutrons are present in an atom of cadmium (Cd) with a mass number of 112?60views