Atomic Structure II PDF

ATOMIC STRUCTURE II Dr. Alya A. Arabi Department of Biochemistry College of Medicine and Health Sciences 1 Isotopes of Hydrogen ➢ 0 neutron (11H) Protium (normal hydrogen) ➢ 1 neutron (21H) Deuterium ➢ 2 neutrons (31H) Tritium 2 Isotopes of Carbon ➢ 6 neutrons (126C) ➢ 7 neutrons (136C)...

ATOMIC STRUCTURE II Dr. Alya A. Arabi Department of Biochemistry College of Medicine and Health Sciences 1 Isotopes of Hydrogen ➢ 0 neutron (11H) Protium (normal hydrogen) ➢ 1 neutron (21H) Deuterium ➢ 2 neutrons (31H) Tritium 2 Isotopes of Carbon ➢ 6 neutrons (126C) ➢ 7 neutrons (136C) ➢ 8 neutrons (146C) encarta.msn.com/.../isotopes_of_carbon.html 3 Atomic Number and Atomic Mass • The atomic number (Z) is the number of protons in the atom's nucleus • The mass number (A) is the number of protons plus neutrons • All the atoms of a given element have the same atomic number • Isotopes are atoms of the same element that have different numbers of neutrons and therefore different mass numbers 12C 6 p+ 6 e6 no vs. 13C 6 p+ 6 e7 no https://www.mdpi.com/2218-273X/8/4/151/htm Atomic Number and Atomic Mass • The atomic mass (atomic weight) of an element is the weighted average mass in atomic mass units (amu) of an element’s naturally occurring isotopes https://quizlet.com/540652645/isotopes-average-atomic-mass-flash-cards/ Isotopes: A Medical Example How is positron emission tomography (PET) imaging technique used to monitor the flow of blood to the brain? A radioactive isotope of oxygen attached to water is injected into the bloodstream. By monitoring the oxygen, PET monitors the blood flow to different regions of the brain while the patient is performing a task. 6 Periodicity of the elements 7 8 http://scienceray.com/chemistry/periods-discovering-the-patterns-within-them/ Rows or Periods These are the quantum numbers 9 Electronic arrangement A new layer (shell) is added for each row or period in the table 10 Shells Shell Shell quantum number (n) # of Type of subshells Subshells maximum # of electrons (2n2) K 1 1 1s 2 L 2 2 2s,2p 8 M 3 3 3s,3p,3d 18 N 4 4 4s,4p,4d,4f 32 11 A group or family 12 Electronegativity Relative ability of atoms to attract electrons 13 Elemental states at 25 oC at 1 atm 14 Metals 15 Non-metals 16 Metalloids 17 Mole Mole is a measure of the amount of a substance. The number of molecules (or atoms) in 1 mole = 6 x 1023 molecules. 6 x 1023 molecules per mole is Avogadro’s number Number of moles = Mass / molar mass Units: (mol) = (g) / (g/mol) 18 Example How many moles of iron does 25.0g of iron (Fe) represents? Atomic mass of Fe = 55.85 g/mol 25.0 𝑔 55.85 𝑔/𝑚𝑜𝑙 = 0.448 moles of Fe 19 Molarity Molarity of a solution is the concentration of that solution measured in moles per litre. A one molar (1M) solution contains 1 mole of a solute in 1 litre of solvent. 20