Physical properties are those which can be observed without any change in composition of the substance. Hence, a is the answer.
The units for molarity is moles of solute per liter of solution which means if you multiply the molarity of a solution by its volume you get how many moles of solute are in the solution. (0.75Mx0.5L=0.375mol NaCl)
Then you can multiply the moles of sodium chloride (0.375 mol) by its molar mass (58.45 g/mol) to get 21.92g of sodium chloride. That means there is 21.92 grams of sodium chloride in 500mL of 0.75M solution. I hope this helps. Let me know if anything is unclear.
1 and 3 only because metal are easily to loss electron while non metal are difficult to loss electron that's why it called heavy elements.
The mass of nucleons (and thus of the nucleus) is roughly 1000 times greater than that of electrons.
Particle mass charge location
protons 1.673*10 ^ - 27 kg 1.6*10 ^ -19 C in the nucleus
neutrons 1.675*10 ^ - 27 kg 0 in the nucleus
electron 9.11 * 10 ^ - 31 kg -1.6 * 10 ^ - 19 C around the nucleus (orbitals)
Protons and neutrons have almost same masses. Mass of electrons is 1/1840 the mass of the protons.
Protons and electrons have the same magnitud of charge with different sign. Protons are positive and electrons are negative. Neutrons do not have charge.
