Atomic Structure - Coach Hyde 2016-2017

Atomic Structure Atomic Notation Atomic Notation represents the number of protons and neutrons in the nucleus of an atom The Atomic Number, Z, represents the number of protons in the nucleus. It also represents the number of e- in a neutral atom. The Mass Number, A, represents the total

number of protons and neutrons in the nucleus of an atom Atomic Notation Atomic Number is 11 # of p+ = 22 protons; # e- = 11 electrons The Mass number is 23

#n= 23-11=12 neutrons Atomic Notation Find the Number of protons Number of neutrons Number of electrons Atomic number Mass number

Atomic Notation If an element has an atomic number of 34 and a mass number of 78 what is the Number of protons Number of neutrons Number of electrons

Complete symbol? Isotopes Atoms of the same element can have different numbers of neutrons (Dalton was wrong) These atoms of the same element would have different mass numbers

These cousins of the same element are called isotopes Most elements occur naturally with varying number of neutrons Hydrogen Isotopes Hydrogen has 3 Isotopes

1 proton and 0 neutrons, protium 1 proton and 1 neutron, deuterium 1 proton and 2 neutrons, tritium (radioactive) Naming Isotopes

To name an isotope properly, we put the mass number after the name of the element Carbon-12 (6 protons and 6 neutrons) Carbon-14 (6 protons and 8 neutrons) Uranium-235 (92 protons and 143 neutrons)

Practice Write the symbol for Cobalt-60 How many protons and neutrons does an atom of mercury-202 have? How many electrons are present in an atom of Copper-63?

Measuring Atomic Mass All of the elements on the Periodic Table have a Mass Number that is in decimal form, or not a whole number why? The Mass number reported on the periodic table is a

weighted average of the isotopes that are naturally occurring Measuring Atomic Mass The Mass Number= the Atomic Mass, or Atomic Weight The mass of 1 mole of an element (unit 4) The number of neutrons and protons present

The mass of one atom of an element relative to an atom of another element Unit: Atomic Mass Unit (amu) The standard for the amu scale is Carbon: Carbon= 6p+ and 6n0= mass standard of 12 amu All other atoms are designated relative to Carbon. I.e. Hydrogen is 1/12th the mass of carbon (or Atomic Mass 1 amu

Mathematics of Isotopes A weighted average means that the numbers of all the objects are not equal, but occur in different amounts Calculated by multiplying the percent of the object (as a decimal number) by its mass for each object and adding the numbers together

Mathematics of Isotopes Copper has 2 isotopes: Copper-63 with a mass of 62.930 amu and 69.09% abundance Copper-65 with a mass of 64.928 amu and 30.91% abundance Isotope Examples

Magnesium has 3 isotopes. 78.99% Magnesium-24 with a mass of 23.9850amu, Magnesium-25 with a mass of 24.9858 amu, and the rest Magnesium-26 with a mass of 25.9826 amu. What is the atomic mass of Magnesium? Boron is 20% B-10 and 80% B-11.

What is the Atomic Mass of Boron? Ions Result from loss or gain of e- by an atom Ions

Ions What is the standard atomic notation for the aluminum atom and ion?