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Atoms, Isotopes, and Ions

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Atoms, Isotopes, and Ions 4.3 4.7, 4.10, 4.11 Ionic Compounds Structure In an ionic compound there is a regular arrangement of oppositely charged particles. – PowerPoint PPT presentation

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Title: Atoms, Isotopes, and Ions


1
Atoms, Isotopes, and Ions
  • 4.3 4.7, 4.10, 4.11

2
Atomic Theory
  • In 1808 John Dalton proposed atomic theory.
  • Daltons theory explained several laws known at
    the time.
  • Law of conservation of matter
  • Law of definite proportions
  • Law of multiple proportions

3
Daltons Atomic Theory (1808)
  1. Elements are made of tiny particles called atoms.
  2. Atoms of a given element are identical.
  3. Atoms of different elements differ from each
    other in some fundamental way.

4
Daltons Atomic Theory (1808)
  • Atoms of one element can join with atoms of other
    elements to form compounds.
  • A given compound is always made of the same
    elements combined in the same ways.
  • Explains the law of multiple proportions and the
    law of definite composition.

5
Daltons Atomic Theory (1808)
  • Atoms are indivisible in chemical reactions.
  • Chemical reactions change how atoms are grouped
    (bonded) together.
  • Explains the law of conservation of matter.

6
Atomic Theory
  • Daltons proposal lead to much research as to the
    nature of the atom.
  • In the late 1800s chemists/physicists determined
    that the atom is made up of smaller, subatomic,
    particles.

7
Atomic Theory - 1910
  • 1896, JJ Thomson demonstrated that atoms can
    emit negative particles.
  • Called these particles electrons.
  • Since atoms are neutral he also proposed that
    they must contain positive particles.
  • These particles were not fully described/named
    until 1919.

8
Atomic Theory - 1910
  • 1910 Lord Kelvin proposed the plum pudding
    model of the atom.
  • Proposed that electrons were scattered within a
    cloud/pudding of positive charge.

9
Atomic Theory - 1911
  • 1911 an experiment was conducted in Ernest
    Rutherfords lab that showed the plum pudding
    model to be incorrect.
  • Experiment was conducted by Geiger and Marsden
    and the findings interpreted by Rutherford.
  • See page 84

10
The gold foil experiment
  • What they did see board
  • What they found see board
  • What Rutherford concluded.

11
Rutherfords Model of the Atom
  • First to propose a nuclear atom.
  • Rutherford proposed that
  • the atom must have nearly all its mass, and
    positive charge, in a central nucleus about
    10,000 times smaller than the atom itself.
  • Most of the atom is empty space and the electrons
    are scattered through out this empty space.

12
A New Model of the Atom
  • Expected based on
  • Plum pudding model
  • Rutherfords model
  • Based on his results

13
Subatomic Particles
  • Rutherford continued to study the atom and the
    positive matter of the atom.
  • 1919, particle named the proton
  • 1932 James Chadwick proposed the existence of a
    third subatomic particle, the neutron.

14
Subatomic Particles
Subatomic Particle Charge Mass, amu Location in atom
Electron (e-) -1 0 amu Outside of nucleus
Proton (p) 1 1 amu Nucleus
Neutron (n) 0 1 amu Nucleus
15
Mass of Subatomic Particles
  • Protons and neutrons have the same mass (in the
    range of 10 -24 g).
  • Neutrons are slightly heavier.
  • Mass is expressed in amu
  • Atomic mass unit (amu) 1/12 the mass of a
    carbon-12 atom

16
Mass of Subatomic Particles
  • The mass of the electron is tiny as compared to
    that of the proton and neutron.
  • Therefore, the electrons mass is considered to
    be 0 amu when calculating the mass of an atom.

17
Subatomic Particles and the Elements
  • Each element has a unique number of protons.
  • Number of protons defines the element.

18
Subatomic Particles and the Elements
  • Since atoms are neutral, for every proton there
    is a/n _________.
  • When atoms interact to form compounds, it is
    their ___________ that intermingle.

19
Terms
  • Atomic number number of protons in an atom
  • Also indicates the number of electrons in the
    atom.
  • Finding atomic number on the periodic table.

20
Terms
  • Mass number sum of the of protons and the
    neutrons in the nucleus of an atom
  • FOR MOST ELEMENTS THE MASS NUMBER IF NOT ON THE
    PERIODIC TABLE.
  • You will be given enough information to determine
    mass number or number of neutrons.

21
Terms
  • Isotopes atoms of a given element that differ
    in mass number
  • Isotopes have the same number of _____________.
  • Isotopes differ in the number of _______.

22
Isotopes
  • Writing atomic symbols for isotopes
  • See board and pg 87

23
FAQ - Isotopes
  • When is mass number found on the periodic table?
  • Whats the atomic mass? Is it the same as the
    mass number?

24
Practice
  • Start 42 on page 110.

25
Ion Formation
  • Ions are formed when atoms gain or lose
    electrons.
  • Proton and neutron number are unchanged when an
    ion forms.

26
Ions - Terms
  • Ion charged atom or group of atoms
  • Cation positively charged ion
  • Metals form cations.
  • Anion negatively charged ion
  • Nonmetals form anions.

27
Ions
  • Na atom
  • _____ protons _____ electrons
  • Na ion
  • _____ protons _____ electrons
  • Name of ion sodium ion

28
Ions
  • Calcium atom
  • _____ protons _____ electrons
  • Ca 2 ion
  • _____ protons _____ electrons
  • Name of ion calcium ion

29
Ions
  • Sulfur atom
  • _____ protons _____ electrons
  • S2- ion
  • _____ protons _____ electrons
  • Name of ion sulfide ion

30
Ion Charge and the Periodic Table
Group Ion Charge e- lost/gained
I A 1 1 e- lost
II A 2 2 e- lost
III A metals 3 3 e- lost
V A nonmetals 3- 3 e- gained
VI A nonmetals 2- 2 e- gained
VII A 1- 1 e- gained
31
Naming Ions
  • Name of a monatomic cation is the name of the
    element
  • Examples
  • Ca 2 calcium ion
  • Al 3 aluminum ion
  • K

32
Naming Ions
  • Monatomic anions are named by changing end of the
    name of the element to ide
  • Example S2- sulfide ion

33
Naming Ions
  • You need to know
  • N3- nitride ion
  • P3- phosphide ion
  • O2- oxide ion
  • S2- sulfide ion
  • F- fluoride ion
  • Cl - chloride ion
  • Br- bromide ion
  • I- iodide ion

34
Ionic Compounds
  • Structure
  • In an ionic compound there is a regular
    arrangement of oppositely charged particles.
  • Ions are arranged in a 3-D crystalline structure
    that maximizes attractive forces and minimizes
    repulsive forces.
  • Also called a lattice structure
  • See page 102

35
Ionic Compounds
  • Physical Properties all are related to the
    structure of the compounds
  • Solids at room temperature
  • Relatively high melting and boiling points
  • No vapor pressure
  • Meaning they dont evaporate
  • Electrolytes
  • Conduct electricity when melted or dissolved in
    water

36
Ionic Compounds
  • The chemical formula for an ionic compound
    represents the lowest, whole number ratio of the
    component ions that has a net charge of zero.
  • Total positive charge total negative charge

37
Ionic Compounds
  • Name the compound by naming the ions.

38
Ionic Compounds
  • Writing formulas for and naming binary ionic
    compounds
  • Magnesium oxide

39
Ionic Compounds
  • Magnesium oxide
  • The formula is the simplest ratio of ions that
    have a net charge of zero.
  • Ions present Mg2 and O2-
  • Formula

40
Ionic Compounds
  • Magnesium chloride
  • The formula is the simplest ratio of ions that
    have a net charge of zero.
  • Ions present Mg2 and _____
  • Formula

41
Ionic Compounds
  • Practice
  • Note we are currently applying the content of
    4.11 and 5.2 (type I binary ionic compounds)

42
Types I Binary Compounds
  • Compound between a metal and a nonmetal
  • Metal forms only one ion
  • Name the cation and then the anion.
  • Name of the cation is the name of the element
  • Name of the anion is the name of the nonmetal
    with the ending changed to ide

43
Monoatomic cations to know
Group Charge on ion examples
IA 1 Na1 sodium (ion) K1 potassium (ion)
IIA 2 Mg2 magnesium (ion)
IIIA metals 3 Al3 aluminum (ion)
44
Monoatomic anions to know
Group Charge on ion examples
VA -3 N3- nitride (ion) P3- phosphide (ion)
VIA -2 O2- oxide (ion) S2- sulfide
VIIA -1 F1- fluoride (ion) Cl1- chloride (ion) Br1- bromide (ion) I1- iodide (ion)
45
Practice
  • Name ? chemical formula
  • Chemical formula ? name
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