1 / 25

Atom of the Present Electrons orbit nucleus in the form of clouds

Atom of the Present Electrons orbit nucleus in the form of clouds. Rutherford’s Atom/Past Electrons orbit nucleus similar as planets to the sun. Proton = + charge Neutron = neutral charge Electron = - charge.

shannonsmith
Télécharger la présentation

Atom of the Present Electrons orbit nucleus in the form of clouds

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. Atom of the Present Electrons orbit nucleus in the form of clouds Rutherford’s Atom/Past Electrons orbit nucleus similar as planets to the sun

  2. Proton = + charge Neutron = neutral charge Electron = - charge

  3. Protons (positive) are bigger than electrons. The part of an atom that gives an element its identity. Neutrons (neutral) are slightly bigger in mass than a proton. Electrons (negative) charge, have a mass of close to zero-negligible

  4. Atomic Mass Units (amu): roughly equal to the mass of a proton or neutron. **the mass of an atom is measured in amu’s 1 amu= 1/12 (mass of 12/6C atom) = 1.66x10^-24g

  5. Particle location Charge(C) Mass (g) Mass (amu) Proton Inside nucleus 1.602 X 10-19 1.673X10-24 1.0073=1 Neutron Inside nucleus 0 1.675X10-24 1.0087=1 Electron Outside nucleus -1.602 x10-14 7.109X10-28 0.0006=0

  6. Atomic numbers • Atoms of each element contain a unique positive charge in their nucleus. • Discovery helped solve the mystery of what makes the atoms of one element difference from those of another. • Atoms identity comes from number of protons in nucleus. • Number of protons in an atom is called atomic number.

  7. Every element has a unique atomic number. • Elements atomic number is just above the chemical symbol on periodic table. • Individual atom is electrically neutral-means number of protons always equal number of electrons.

  8. Electron Number • An Element’s atomic number also indicates number of electrons in its atoms. • Atom can lose or gain its electrons, giving an overall positive or negative charge.

  9. Ions Ions are atoms that have lost or gained one or more electrons giving them a positive or negative charge!

  10. If an ion gains an electron it has a negative charge. If an ion looses an election it has a positive charge. For example: Na (Sodium), has originally 11 electrons but when an electron is lost it becomes a postive ion. Na +

  11. What causes an atom to become an ion? • When an atom loses or gains one or more electrons it acquires a net electrical charge called an ion. • The net charge of an ion is found by subtracting the number of electrons from the number of protons • Charge of Ion = number of protons – number of electrons

  12. A neutral magnesium atom (atomic number=12) has 12 protons/electrons. If it loses 2 electrons it becomes an ion with a charge of 2+. Number of protons 12 Number of electrons - 10 Charge of Ion 2+

  13. Ion Electrons Protons 19. Cu²+ 20. F- 29 9 27 10

  14. 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 Hmm

  15. 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

  16. Differences between isotopes? • Isotopes react in the same way as others of the same element • The major difference between two isotopes is their mass – Isotopes with more neutrons have a higher mass than those with fewer neutrons • “Heavy” and “light” are often used to describe an isotope

  17. 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.

  18. Atomic mass: weighted average of the masses of the existing isotopes of an element. Atomic Number/ number of protons Atomic mass

  19. Q. What is the name of the Nitrogen isotope with 7 protons and 12 neutrons? A. Nitrogen-19

  20. Examples AtomProtonsNeutronsElectrons iodine-128 potassium-41 53 19 75 21 53 19

  21. Mass Number – the sum of an isotope’s protons and neutrons. • To name an isotope using chemical symbols, simply place the atom’s mass number to the upper left of the element symbol. For example 37Cl. #neutrons = atomic mass – atomic number 37 – 17 = 20 neutrons

  22. 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 = 30. There are 30 neutrons. 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+

  23. Isotope Symbols Mass number (M) Ba2+ 141 Charge 56 Atomic number (Z)

  24. Number of protons = Z Number of neutrons = M – Z charge = Z– Number of electrons

More Related