Atomic Structure: Protons, Neutrons, and Elements

• Matter is made from elements, and atoms are the building blocks of elements.
• The question is posed: What are atoms made from?
• Helium is represented as a sphere, like any other atom.
• After years of study, it has been determined that an atom consists of a tiny nucleus (1 femtometer) surrounded by an electron cloud (100,000 femtometers, or 100 picometers).
• The nucleus comprises protons and neutrons.
• 1 Ångström (Å) is equivalent to 100,000 femtometers (fm) or 100 picometers (pm).
• The number of protons in an atom determines the element. As an example, 5 protons indicate boron, and 79 protons indicate gold.

SI Unit Conversion Factors

• Yottametre (Y): 1 Ym = 10^24 meters
• Zettametre (Z): 1 Zm = 10^21 meters
• Exametre (E): 1 Em = 10^18 meters
• Petametre (P): 1 Pm = 10^15 meters
• Terametre (T): 1 Tm = 10^12 meters
• Gigametre (G): 1 Gm = 10^9 meters
• Megametre (M): 1 Mm = 10^6 meters
• Kilometre (k): 1 km = 10^3 meters
• Hectometre (h): 1 hm = 10^2 meters
• Decametre (da): 1 dam = 10 meters
• Metre: 1 m = 1 meter
• Decimetre (d): 1 dm = 0.1 meters
• Centimetre (c): 1 cm = 0.01 meters
• Millimetre (m): 1 mm = 0.001 meters
• Micrometre (μ): 1 μm = 0.000001 meters
• Nanometre (n): 1 nm = 0.000000001 meters
• Picometre (p): 1 pm = 0.000000000001 meters
• Femtometre (f): 1 fm = 0.000000000000001 meters
• Attometre (a): 1 am = 0.000000000000000001 meters
• Zeptometre (z): 1 zm = 0.000000000000000000001 meters
• Yoctometre (y): 1 ym = 0.000000000000000000000001 meters
• An element with a given number of protons can have different numbers of neutrons, which creates isotopes.
• Natural hydrogen contains approximately 0.01% deuterium, which has one neutron.
• Uranium isotopes include Uranium-234, Uranium-235, and Uranium-238.
• Uranium-234 has 92 protons and 142 neutrons and is not fissile.
• Uranium-235 has 92 protons and 143 neutrons, and most nuclear reactors use fuels containing fissile Uranium-235.
• Uranium-238 has 92 protons and 146 neutrons and makes up over 99% of the naturally occurring isotopes of uranium on Earth.
• The periodic table reports the standard atomic weight as the % average of the isotopes
• Atomic weights of uranium:
  • U-233 has a relative atomic mass of 233.0396355(29).
  • U-234 has a relative atomic mass of 234.0409523(19) and an isotopic composition of 0.000054(5).
  • U-235 has a relative atomic mass of 235.0439301(19) and an isotopic composition of 0.007204(6).
  • U-236 has a relative atomic mass of 236.0455682(19).
  • U-238 has a relative atomic mass of 238.0507884(20) and an isotopic composition of 0.992742(10).
• The fission reaction of Uranium-235 (discovered in 1938) is a nuclear reaction that produces a lot of energy.

Fission Reaction of U-235

• Bombarding a U-235 atom with a neutron converts it into other elements, releases three neutrons, and is adapted to make nuclear bombs.
• Nuclear power uses nuclear reactions to produce electricity with no CO2 emissions but carries the risk of accidents.
• The graph shows the trend of nuclear power generation
• The Barakah Plant, built by a Korean company, with four units, is the first nuclear energy plant in the Arab World with a total nameplate capacity of 5600 MW. It is intended to supply up to 25% of the UAE's electricity needs.

Uranium Enrichment

• Most commercial nuclear power reactors require uranium enriched in the U-235 isotope.
• Light water reactors (PWR and BWR) require uranium to be enriched from 0.7% to 3-5% U-235 and nuclear bombs require enrichment to near 90% U-235.
• Enrichment accounts for almost half the cost of nuclear fuel and about 5% of the total cost of electricity generation.
• The commercial enrichment process involves gaseous uranium in centrifuges.
• Uranium oxide must be converted to a fluoride before enrichment so that it can be processed as a gas at low temperature.
• Enriching uranium with the U-235 isotope involves creating gaseous molecules of UF6, then centrifuging the gas.
• In terrestrial samples of copper, Copper-63 makes up 69% and Copper-65 makes up 31% with a standard atomic weight of 63.55.

Fundamental properties of subatomic particles

• Fundamental properties include the mass, charge, and spin.
• Each of these particles has a spin of ½.
• Mass for Electron, 9.109 382 × 10^-28 grams, 5.485 799 × 10^-4 amu*, -1.602 176 × 10^-19 coulombs, -1 charge.
• Mass for Proton, 1.672 622 × 10^-24 grams, 1.007 276 amu*, +1.602 176 × 10^-19 coulombs, +1 charge.
• Mass for Neutron, 1.674 927 × 10^-24 grams, 1.008 665 amu*, 0 coulombs, 0 charge.
• 4.0 grams of helium contain 6.02 x 10^23 atoms (Avogadro's number).
• The decimal number next to each element in the periodic table, if used in grams, corresponds to a mole of that element.
• A mole of an element has Avogadro's number of atoms, just as a dozen atoms is 12 atoms.
• To react one mole of sodium with one mole of chlorine, weigh out 22.99 grams of sodium and 35.45 grams of chlorine.
• Mass is an inherent fundamental property that is difficult to explain: look at the manifestation of mass.
• Isaac Newton (1642 - 1727) stated that mass is a measure of inertia and inertia is resistance to being moved.
• The greater the mass, the more effort is needed to move it.
• The mass of a particle (m₁) is a measure of its ability to attract another particle with mass (m₂).
• Attraction is a consequence of a force that exists between the two particles, called gravity, and is a fundamental force of nature.
• Gravity is defined as the force of nature that gives life to matter.
• The gravitational force of attraction between two particles with mass is quantified as:

Gravitational Force

• Formula: F = -(Gm₁m₂)/r², where G = 6.67 x 10^-11 Nm²/kg² (gravitational constant).
• On Earth, F = -mg, where g = 9.8 ms⁻² (standard constant of acceleration).
• An object is considered to have more energy when it is lifted off the floor.
• Quantifying energy change due to Earth's gravity is expressed as E = mgh, where the energy is positive when h is positive.
• A man walking freely at sea level is considered to be in a free state and his potential energy is zero.
• A man in a well is no longer free and is in a bound state, where E = mgh (h is negative). We say the potential energy of a man in a well is negative.
• Attempting to rescue the man using a rope,
• For a man using a rope, the position can be any value between -10 and zero, and the energy is any value between -10 and 0.
• When n = 1, the man is in the lowest accessible energy state and is a special bound state called the ground State. There is a driving force to be in the ground state and can easily fall from n = 3 to n = 1
• Between n = 1 and n = 11 are higher energy excited state, the man can easily fall from an excited state to the gorund state
• When n =11, the highest accessible excited state. This state is equivalent to the free state. Thus, the enrgy needed to excite the man to the n=11 state, is the energy needed to separate him from the well.