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The Atom Contains 3 subatomic particles: The dense center ( nucleus ) of the atom contains: Neutron - a particle with no charge. Proton - a particle with a positive charge. Electrons are tiny particles that move around the nucleus. - negative electrical charge.
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The Atom Contains 3 subatomic particles: The dense center (nucleus) of the atom contains: Neutron - a particle with no charge. Proton - a particle with a positive charge. Electrons are tiny particles that move around the nucleus. - negative electrical charge. - same # of positive and negative charges = neutral.
Explain and draw a Bohr model of an atom. • Understand the movement of electrons when energized. • Understand and perform a Flame Test • Compare and contrast positive and negative ions. Key Words Orbit Planetary model Flame Test
Bohr (1913) • hypothesized electrons occupy precise positions. • specific distances around the nucleus called orbitsorshells. • only a specific number of electrons can occupy each orbit. • called the “planetary model”
Electrons occupy the closest orbital first. 1st– holds two electrons (e-) 2nd– holds eight e- 3rd – holds eight e- Ever element has a different number of electrons.
Elements give off a unique colour of light when heated - used to detectthe presence of a metal This is known as a flame test. Bohr model explains the colours as “jumps” electrons make when energy is added.
Electrons are always moving - haveenergy. Given more energy(heat, light, electricity) electrons will jump up to a new further orbit. When electrons drop back down to previous orbit they release the energyas light. Elements have different number of electrons – different “jumps” – different spectrum of colour.
Energy level 4 Energy level 3 Energy level 2 Ground State Energy level 1
Isotopes: Atoms of the same element with the same number of protons but a missing or extra neutron. helium helium isotopes The nucleus of some isotopes are unstable and break apart over time - radioactivity.
The Atom Contains 3 subatomic particles: Neutron–nucleus particle with no charge. - can vary within an element - ISOTOPES. Proton– nucleus particle with a positive charge. Electrons–negative particles move in specific orbits. - e- jump/drop orbits releasing energy. - same # of positive and negative charges = neutral.
How many electrons are able to occupy: the first orbit? the second orbit? the third orbit? Draw a Bohr model of the atom carbon which has six electrons. Draw a Bohr model of the atom aluminum which has 13 electrons.