Isotopes
Isotopes. Isotopes. Isotopes are atoms that have the same number of protons but different numbers of neutrons Most elements in the first two rows of the periodic table have at least 2 isotopes with one being more common than the other
Isotopes
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Presentation Transcript
Isotopes • Isotopes are atoms that have the same number of protons but different numbers of neutrons • Most elements in the first two rows of the periodic table have at least 2 isotopes with one being more common than the other • In nature, elements are almost always found as a mixture of isotopes
Hydrogen Deuterium Tritium Isotopes of Hydrogen • For example, the most common isotope of hydrogen has no neutrons at all • There's also a hydrogen isotope called deuterium, • with one neutron, and another, tritium, with two neutrons. Most common isotope Neutron Proton
More fun with Isotopes • To identify an isotope more specifically, chemists add a number after the elements name. • ex. Carbon-11 Carbon-12 Carbon-14 • This number is called the isotope’s mass number and is the sum of the isotope’s number of protons and neutrons. • For example, an atom with 17 protons and 20 neutrons has a mass number of 37.
Q. What is the mass of the Nitrogen isotope with 7 protons and 12 neutrons? A. Nitrogen-19
Examples AtomProtonsElectronsNeutrons 53 19 75 21 iodine-128 potassium-40 53 19
Isotope Symbols Mass number Ba2+ 141 Charge 56 Atomic number
How many protons, neutrons, and electrons are present? 56 26 STEP 1: The atomic number in the lower left corner = 26 protons. The difference between the mass number and the atomic number is 56 – 26 = 30neutrons STEP 2: The charge on the ion, 2+ shows us that there are 2 more protons than electrons, indicating that there are 24 electrons. Fe 2+
Isotope Symbols Mass number Ba2+ 141 Charge 56 Atomic number Step 1) 141- 56= 85 neutrons Step 2) 56 electrons -2 = 54 electrons
