Lecture 3 Flashcards
(28 cards)
What’s atomic mass?
protons + #neutrons
Whats atomic number?
protons
What’s an isotope?
It’s a version of an atom/element. This means there is the same number of protons but a different number of neutrons.
What are stable isotopes?
Nuclei do not tend to lose particles.
What are non stable/radioactive isotopes?
Nucleus gives off particles of energy as it decays spontaneously.
Definition of ionizing radiation.
Its the particles of energy that are given off by non stable isotopes as the nucleus in the isotope decays.
What kind of particles are emitted from non stable isotopes (ionizing radiation)?
X ray(s) or subatomic particles. Alpha or beta particles have energy to free electrons from atoms/molecules and ionize them.
What is non-ionizing radiation?
It is any type of electromagnetic radiation that doesn’t have enough energy per quantum, therefore, it cannot ionize atoms or molecules.
Give 3 examples of non-ionizing radiation.
- Phones/mobiles
- Radio-waves
- Electropower transmission
etc
What are ions?
They are atoms/molecules that have a positive or negative charge. So #electrons CANNOT EQUAL #protons. So the net charge cannot equal to zero.
What is a chemical bond?
It’s an attraction (bond) that holds two atoms together.
Chemical bonds: What are covalent bonds?
Bond between the valence electrons of two atoms, where the valence electrons are shared.
Chemical bonds: What are polar covalent bonds?
This is when the electrons are not shared equally between two atoms.
What is electronegativity?
It’s how much an atom can attract electrons.
Chemical bonds: What are hydrogen bonds?
It’s when a hydrogen atom is bounded to an electronegative atom and interacts with another atom of a different molecule that’s also electronegative.
Chemical bonds: What are ionic bonds?
When two atoms pair together. One with low electronegativity and one with high electronegativity so that one atom can attract electrons easier than the other, which allows the high electronegativity atom to steal the valence electrons from the other atom.
Chemical bond: What are van der Waals interactions?
They help stabilize molecules and influence the melting point of fatty acids. These happen when non-permanent positive and negative areas of molecules attract to each other. (They’re weaker than hydrogen bonds)
What does it mean to be polar? And where does water stand in this?
Polar means that it allows the formation of h-bonds.
What does it mean to be hydrophilic? Name 3 things
Love water, they’re polar and dissolve readily in water.
What does it mean to be hydrophobic? Name 3 things
Fear water, they’re non-polar and don’t dissolve readily in water.
How do H-bonds affect water molecules?
They cause them to stick together (become cohesive) and stick to other certain surfaces (become adhesive).It allows capillary action.
What’s surface tension?
It’s a measure of how difficult it is to break the surface of a liquid.
What’s specific heat?
It’s the amount of heat absorbed or lost to allow the change in temperature of 1 degree celsius.
Explain the specific heat of water.
Water has a high heat capacity because of the H-bonds. When it’s heated, the H-bonds must be broken by the energy being absorbed. The energy, then increases the movement of the water particles. Water, thus resists temperature change.
