1 / 10

Masses of Atoms

Masses of Atoms. Atomic mass. Nucleus contains most of the mass of the atom Protons and neutrons are far more massive than electrons Mass of a proton or neutron is approximately 1.6726 X 10 -24 This mass of a proton is about 1,836 times the mass of an electron. Mass of atomic particles.

tarak
Télécharger la présentation

Masses of Atoms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Masses of Atoms

  2. Atomic mass • Nucleus contains most of the mass of the atom • Protons and neutrons are far more massive than electrons • Mass of a proton or neutron is approximately 1.6726 X 10-24 • This mass of a proton is about 1,836 times the mass of an electron

  3. Mass of atomic particles • Not measured in normal units • Amu – atomic mass unit

  4. Protons Identify the Element • Each element can be described by the number of protons it has • The number of protons in an atom is known as its atomic number • What is the atomic number for the following atoms??? • Nitrogen (N), Oxygen (O), Hydrogen (H), Boron (B), Silver (Ag), Antimony (Sb)

  5. Identifying an Element • If we know one of the following we then know also the other two: • Atomic number • Name of the element • Number of protons

  6. Mass number • The mass number of an atom is the sum of the number of protons and the number of neutrons in the nucleus of an atom. • Mass number

  7. Neutrons in an atom • By using the atomic number and the mass number (which is also called the atomic mass) you can find how many neutrons are in an atom of an element. • Number of neutrons = mass number – atomic number

  8. Differing number of Neutrons • Some elements can be found with differing number of neutrons • Isotopes – atoms of the same element that have different numbers of neutrons • Some elements such as Carbon have different Isotopes there is a Carbon-12 isotope and a Carbon-14 isotope… which means that Carbon-12 isotope has 12 neutrons and Carbon-14 isotope has 14 neutrons

  9. Atomic mass number • Decimal places are found in the mass number… this is because the mass number is the average atomic mass of an element • Average atomic mass – the weighted-average mass of the mixture of its isotopes • For example • If we had 5 boron atoms randomly found in nature • 4 Boron-11 and 1 Boron-10 • How would we find the average atomic mass of these atoms??? • The average atomic mass of boron is close to the mass of its most abundant isotope, boron-11

  10. Draw a diagram • On a blank sheet of paper please draw a diagram for the nucleus of each of the following: Carbon-12, Carbon-13, and Carbon-14. And Identify which Carbon Isotope is found more often (hint you can calculate this or it is in your book). • Be sure to put the correct amount of protons and neutrons (using different colors) – also write underneath how many protons and neutrons for each isotope. • Correctly label each isotope and color coordinate your protons and neutrons (place a key in the corner to correctly identify which are protons and which are neutrons). • An example of how to draw a nucleus is Figure 8 on page 515. • At the bottom of the page explain what an isotope is • and reference your drawing.

More Related