Atomic Structure Ch. 3- Test 2 Flashcards
What is an element?
All units (atoms) of an element share specific chemical behaviors.
A substance that cannot be broken down into a simpler substance
(only one kind of element)
What is an atom?
The smallest single unit of an element, retaining all of its chemical behaviors
Chemical Behavior describes:
how elements interact with each other during chemical reactions
ALL matter is composed of ____
Atoms!
What three subatomic particles are atoms composed of? (within the nucleus)
- Protons or Atomic Number (Positively Charged)
(Top right # on periodic table) - Electrons smaller then protons, that zoom around protons making an electron cloud
(Negatively Charged, much smaller in mass then proton and neutrons) - Neutrons (Uncharged)
Rutherford introduced the nuclear model, which described the atom as……
containing a small, dense, positively charged center surrounded by a negative cloud of electrons.
He called the center of the atom the Nucleus!
Niels Bohr showed, that the electrons…
could only exit at certain energy levels, in prescribed “orbits” or energy levels, at set distances from the nucleus
The atom is essentially ___
empty space
One unit of charge is a___
Coulomb (C)
Atoms in their normal state are ___ because of the number of electrons = # of protons.
Neutral
A positively charged atom has ____ protons than electrons.
More
A negatively charge atom has
____ protons than electrons
fewer
In physics “A” number represents:
On a Periodic Table: Top number on the left
the mass number (total number of protons and neutrons in an atom)
In physics, “Z” number represents:
On a Periodic Table: Bottom number on the left
the atomic number (number of protons in the nucleus)
If the atom is neutral in charge, how can you determine the number of electrons?
Look at the periodic table!
(Add “A” and “Z” numbers together)
- Mass Number
- Atomic Number
How many electron shells are there?
7!
Physicists call the shell number n the ____
principal quantum number
How many kinds of atoms are there?
118, which are the smallest part of an element
All elements have the same number of ___ and ____
protons and electrons
___ behavior is the making or breaking of physical connections between atoms in which they “share” components (electrons)
Chemical
Are electrons particles, or waves?
they are considered to be both waves and particles, but behave like waves in most experiments
What type of experiment was used to describe if light, x-rays, and electrons are particles or waves?
Double-Slit Experiment
Or
(Two-Slit)
The ____ happens when an orbital electron absorbs all of the energy of a light (a photon) and is ejected from the atom.
Photoelectric Effect!
Who is responsible for finding/explaining photoelectric emission, the photoconductive effect, and the photovoltaic effect?
Albert Einstein