Unit 3. Oxford. 2nd ESo. the material world atoms

1. 3. THE MATERIAL WORLD: ATOMS
Oxford education
Humanitas Bilingual School
2 ESO

2. 1. A JOURNEY TO THE CENTRE OF MATTER
 All matter is made up of atoms.
 Greeks (2500 years ago): atoms=“indivisible” in greek
 Nowadays>>smaller particles (LHC*)
 The size of atoms: video
 Hydrogen atom: 0,000 000 000 1=10-10m
 What are they like?
 Can´ t see them
 Not indivisible
 Not balls of matter
 Electrical phenomena
*Large Hadron Collider at CERN in Geneve

3. 2. ELECTRICAL PHENOMENA
 Atoms are neutral
 Some atoms can get electric charge: Cause
attraction and repulsion.
 There are positive and negative charges inside the
atoms.
 Electrical charges of the same type>> repel
 Electrical charges of different signs>>attract

4. 3. INSIDE THE ATOM: ITS PARTICLES
 3 types of subatomic particles:
 Electrons, Protons, Neutrons
 Electrons:
 Located in the shell of the atom
 Mass 1840 times smaller than proton mass (insignificant)
 Negatively charged
 Protons:
 Located in the nucleus of the atom
 Mass of 1u*
 Positively charged
 Neutrons:
 Located in the nucleus of the atom
 Mass of 1u*
 No electrical charge=neutral
* u= atomic unit, 1u=1,66x 10-27kg

5. ACTIVITIES
1. Find information about the LHC and what its
purpose is.
2. Write the dimensions of…
1. Size of an hydrogen atom in m (meters):
2. Mass of a proton in kg:
3. Complete the chart
Electron Proton Neutron
Location
Mass
Electrical
charge

6. CHARACTERISTICS OF AN ATOM
 The number of electrons is the same as the
number of protons in neutral atoms. (electrons and
protons have same charge, but opposite sign)
 An atom is basically empty and has a nucleus
and a shell or orbitals with electrons.
 Protons and neutrons are in the nucleus
 Electrons move around the nucleus at very high
speeds. Models to represent it.
Planetary model,
Bohr model
Current model: with
electron clouds

7. SCIENTIST AND THEIR DISCOVERIES
 Greeks: atoms are indivisible balls of matter
 Thomson: discovered particles negatively charged
at the end of the 19 century
 Rutherford: discovered in 1911 that the atom is
most of it empty space and in the nucleus there is
positive charge.
 James Chadwick discovered neutrons in 1932

9. BUILD AN ATOM Element flashcards

10. ACTIVITIES
1. Complete the chart with the information
ELEMENT ELEMENT
SYMBOL
PROTONS
Z
PROTONS
+
NEUTRONS
A
NEUTRONS ELECTRONS
Mg 24
Li 7
PHOSPHORUS 16
NICKEL 59
9 10

11. ISOTOPES
 Atom that has a different mass number to the
standard of that element.
 They have the same Z (number of protons), but
different A (mass number, different number of
neutrons).
 Atomic mass: average mass of the mass number
of the isotopes according to their relative
abundance.

12. 4. IONS
 Atoms that are not neutral>>`>possitive or negative
charge
 The number of electrons changes. (as the number
of protons can´t change)

14. ACTIVITY
1. Do this online quizz: QUIZZ
2. Complete the chart
Type of ion ELEMENT
SYMBOL
Z ELECTRONS
Be2+
Chloride anion Cl-
Al3+
Co3+
N3-

15. 5. THE ORGANIZATION OF ATOMS IN MATTER
 A simple substance is
made up of atoms from the
same chemical element.
 A compound substance is
made up of atoms from
different chemical elements

18. CHEMICAL FORMULA
BUILD A MOLECULA MOLAR MASS