Chapter 2A Flashcards
(48 cards)
What is matter?
Anything that takes up space and has volume and mass.
What is energy?
The ability to do work.
What are elements?
A substance that consists of only one type of matter.
Approximately how many elements are essential to life?
25
What are atoms?
Smallest unit of an element that still retains the characteristic of the element.
What are the three sub-atomic particles?
- Protons
- Neutrons
- Electrons
Protons charge, mass, and location
Positive, mass of one, inside the nucleus
Neutrons charge, mass, and location
No charge, mass of one, inside the nucleus
Electrons charge, mass, and location
Negative, mass of approx. 0, surrounding the nucleus
What is atomic number
The number of protons in the nucleus
What is mass number
The total number protons + neutrons
What are Ions?
An atom that has gained or lost electrons
What are isotopes?
Alternate forms of atoms
what is the atomic weight?
The average of all the different types of that element. (isotopes)
what are radioactive isotopes?
An unstable isotope
What are molecules?
Two or more combined atoms.
what are compounds?
Two or more combined atoms of different elements.
What are orbitals?
The path an atom can take around the nucleus.
How many electrons can be held in each orbital?
two
What are energy shells
where electrons can reside
How many electrons can be held in each energy shell
2n²
How does the position of an electron relate to
its energy level?
The closer to the nucleus the lower the energy
What are the valence shell and valence electrons?
The outermost occupied shell
What is electronegativity?
The ability of an element/atom to attract electrons
