Lecture 20
No description yet. This curated deck is ready for daily study.
Card preview (24)
Rutherford found that an atom is?
Mostly empty space
A diameter of the atom is ___ times that of its nucleus
100,000
The nucleus of an atom is largely?
Unaffected by chemical reactions involving the electrons and vice versa.
The energies available in the nucleus are?
much greater than the energy available among electrons.
Why is the energy in the nucleus greater than the energy among electrons?
Most of the mass of the atom is in the nucleus, meaning most of the energy resides there as well
What is a form of energy?
Mass
Energy =
mass x (speed of light)^2, where c(speed of light) is a large number (300,000 km/s), so even a small mass can possess a lot of energy
Who came up with the equation E=mc^2
Einstein
What does Einstein’s famous equation for energy mean?
A given amount of mass can be converted into a specific amount of energy in any form, and vice versa
What is an example of the energy equation?
When an archer draws a bow, its elastic potential energy increases in the bent bow, and the mass of the bow slightly increases because E and m are directly proportional
Proton comes from the word protos, which means?
The first one
What are the characteristics of a proton?
They have a +1 charge
The atomic number is?
The number of protons in an atom dictates the number and arrangement of electrons and defines chemical behavior.
The atomic mass is composed of the mass of?
protons and neutrons
Neutrons have?
no electrical charge, and approximately the same mass as a proton, though they are slightly heavier
What gives an atom its size?
electrons
What gives an atom its mass?
the nucleus
What are isotopes?
Elements with different numbers of neutrons, meaning they have a different mass. They can be stable or radioactive
Are there more stable or radioactive isotopes?
Radioactive
The number of neutrons has an important consequence on the?
stability of the nucleus, as they are what hold the nucleus together
What is the fundamental law of static electricity?
Like charges repel
Given that within the nucleus there is a large number of positively charged protons packed closely together there should be?
a repulsive force between the positively charged protons
How does a nucleus stay stable and not explode from the repulsive force?
Strong Force, one of the four fundamental forces of nature
Strong force is an?
Attractive force capable of balancing or overcoming the electrical repulsion at the scale of the nucleus