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+. +. +. Atoms The Building Blocks of Matter. -. -. -. +. +. +. -. -. +. +. -. -. -. Reminder: Matter is. Anything that has mass and takes up space (volume) Examples: A brick has mass and takes up space A desk has mass and takes up space
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+ + + AtomsThe Building Blocks of Matter - - - + + + - - + + - - -
Reminder: Matter is... • Anything that has mass and takes up space (volume) • Examples: • A brick has mass and takes up space • A desk has mass and takes up space • A pencil has mass and takes up space • Air has mass and takes up space Matter is also made up of small particles called ATOMS
Atomic Structure • Atoms are the smallest possible unit into which matter can be divided, while still maintaining its properties. • 2 areas in the atom: • Nucleus: middle of the atom; most of the mass • Electron Cloud: surrounds the nucleus; mostly empty space (Atom is mostly empty space) - + - + + - + -
Atomic Structure 3 subatomic particles: • protons • neutrons • electrons - + - + + - + + - -
Atomic Structure • Electrons • Tiny, very light particles • Negative electrical charge (-) • Located in the Electron cloud • Protons • Large and heavy • Positive charge (+) • Located in the Nucleus • Neutrons • Large and heavy • Neutral- No electrical charge (o) • Located in the Nucleus - +
- - - + + + + - - + + - + + - - Protons (+) Additional Information: • Help identify the atom • Equal to the atomic number of the atom • Contribute to the atomic mass • Equal to the number of electrons in a neutral atom +
- - - + + + + - - + + - + + - - Neutrons (o) Additional Information: • Contribute to the atomic mass • Can be a different number for atoms of the same element (isotopes) • ex. Carbon-12 has 6 neutrons & Carbon-13 has 7 neutrons
- - - + + + + - - + + - + + - - Electrons (-) Additional Information: • Move so rapidly around the nucleus that they create an electron cloud • Equal to the number of protons in a neutral atom • Involved in the formation of chemical bonds between atoms -
- - - - - - - - - - - - - - - - - - + + - - - - - - - - - - - - - - - - - - Sub-Atomic Particles Weight Comparison (protons, neutrons, electrons) Neutron = 1.6749286 x10-27 kgProton = 1.6726231 x10-27 kgElectron = 9.1093897 x10-31 kg 1839 electrons = 1 neutron 1836 electrons = 1 proton How do you think the mass of a neutron compares to that of a proton? 1 neutron ≈ 1 proton
Atomic Model =Nucleus
+ + + The Nucleus • Protons and neutrons are grouped together to form the “center” or nucleus of an atom. Notice that the electrons are not a part of the nucleus - - -
QUARKS • Particles that make up protons and neutrons Notice the smaller particles that make up this neutron after you take a closer look. Notice the smaller particles that make up this proton after you take a closer look. + What do you notice about the number of quarks in the neutron and proton?
Periodic Table • The periodic table organizes the different types of atoms (elements) in a particular way. • You can predict the physical and chemical properties of the elements. WE WILL HAVE AN ENTIRE UNIT ON THIS!
What’s in a square? • Different periodic tables can include various bits of information, but usually: • atomic number • chemical symbol • chemical name • atomic mass (weight)
+ + + Atomic Number Elements are organized on the table according to their atomic number, usually found near the top of the square. • Atomic number: The number of protons in the nucleus of an atom • The atomic number is unique to that element. No two elements have the same atomic number. - What would be the atomic number of this atom? - - What type of atom is this?
+ + + Mass Number Mass Number = # of protons + neutrons in the nucleus of an atom • Expressed in Atomic Mass Units (amu) • Each proton or neutron has a mass of 1 amu What would be the mass number of this atom? - + 3 4 - 3 protons + 4 neutrons = a mass number of 7 amu Why did we not account for the electrons when calculating the mass number? -
Atomic Mass • The weighted average of the masses of all the naturally occurring isotopes of an element • The average considers the percent abundance of each isotope in nature • Found on the periodic table of elements • Example What would be the atomic mass (≈) of Hydrogen if these three isotopes were found in the following percentages (99.9, 0.015, 0) respectively? - + + + - - Hydrogen (Protium) Mass # = 1 amu Hydrogen (Deuterium) Mass # = 2 amu Hydrogen (Tritium) Mass # = 3 amu If you simply average the three, 2 amu (1 amu + 2 amu + 3 amu/3) would be the atomic mass, but since 99.9% of the Hydrogen is Protium, the atomic mass is around 1 amu (.999 x 1 amu)
Isotopes • Atoms that have the same number of protons, but have different numbers of neutrons and mass numbers • Examples Hydrogen - - - + + + - Hydrogen (Protium) Hydrogen (Deuterium) Hydrogen (Tritium)
Mass # Isotopes • Isotopes: Atoms of the same element with different mass numbers. • same number of protons; different number of neutrons Nuclear symbols Atomic # carbon-12 carbon-14
Building Atoms Using the whiteboard and the proton, neutron, and electron pieces, build the following atoms, and determine their atomic and mass numbers.