SCHEDULE CHANGE. A planned change or a flight number/time change which can occur up to more than 72 hours prior to the flight's scheduled. departure. Examples - Change of flight times, change of flight numbers, reduction of service, discontinuation of all service. in a market. American uses an automated schedule change process up to 72 hours prior to departure. Through this automated. process all schedule changes are sent to the booking source for notification.
Describe the particles that make up the nucleus of an atom in terms of mass and charge. Protons, neutrons and electrons. Protons have a relative mass of 1 and a charge of +1, they are found in the nucleus of an atom.
Atoms are composed of three type of particles: protons, neutrons, and electron. Protons and neutrons are responsible for most of the atomic mass e.g in a 150 person 149 lbs, 15 oz are protons and neutrons while only 1 oz. is electrons. The mass of an electron is very small (9.108 X 10-28 grams). Both the protons and neutrons reside in the nucleus. Protons have a postive (+) charge, neutrons have no charge --they are neutral. Electrons reside in orbitals around the nucleus. They have a negative charge (-). It is the number of protons that determines the atomic number, e.g., H = 1. The number of protons in an element is constant (e.g., H=1, Ur=92) but neutron number may vary, so mass number (protons + neutrons) may vary.