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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.

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

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  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

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