The document discusses the basic constituents of atoms: electrons, protons, and neutrons. It notes that electrons have a negative charge and small mass, protons have a positive charge and greater mass, and neutrons have no charge and a mass similar to protons. Almost all an atom's mass is contained in the nucleus, which is made up of protons and neutrons. The document also defines key atomic concepts like nucleon number, proton number, and isotopes.

1. Constituents of the Atom © my-chem-tutor.blogspot.com -1 0 +1 relative charge 1/1836 1 1 relative mass 0.000549 u Electron cloud electron 1.0087u nucleus neutron 1.0073u nucleus proton mass location particle 99.9% of an atom's mass is found in the nucleus! Atoms as viewed under HRTEM

2. Charged Particle Motion Why is the trajectory more acute for an electron compared to a proton? Food for thought © my-chem-tutor.blogspot.com

3. Nucleon Number (Mass Number), A, - the no. of protons + neutrons in the nucleus Proton number (Atomic Number), Z, - the no. of protons in the nucleus - the no. of electrons Nucleon & Proton Number X A Z Nucleon No. = p + + n 0 Proton No. = p + = e - © my-chem-tutor.blogspot.com

4. atoms of the same element with the same no. of protons but different no. of neutrons. i.e. same proton no. but different nucleon no. Isotopes © my-chem-tutor.blogspot.com 24 12 25 12 26 12 11% 14 12 12 Mg 10% 13 12 12 Mg 79% 12 12 12 Mg Abundance No. of n 0 No. of e - No. of p + Isotope