Question

How many protons, electrons, and neutrons are present in X⁻ if the atomic number of X is 17 and the mass number is 35?

What information do you get from the following figures about the valency, atomic number and mass number of atoms X, Y and Z? Give your answer in a tabular form.

The picture shows the symbol for sodium. What can be concluded about sodium from the symbol?

Read the given passage and answer the questions that follow based on the passage and related studied concepts. A large amount of research and many studies have been conducted to ensure success in new treatment plants using chlorine as a disinfectant. A leading advantage of chlorination is that it has proven effective against bacteria and viruses; however, it cannot inactivate all microbes. Some protozoan cysts are resistant to the effects of chlorine. Chlorine inactivates a microorganism by damaging its cell membrane. Once the cell membrane is weakened, chlorine can enter the cell and disrupt cellular respiration and DNA activity (two processes that are necessary for cell survival).