History of the Atom
Who created the modern periodic table?
Dmitri Mendeleev
An Isotope is an element that has the same number of protons and electrons but different _______
Neutrons
What period and group would you find Oxygen?
Period 2, Group 16
Proton = Positive
Neutron = Neutral
Electron = Negative
What are Valence Electrons?
Electrons that located in the outermost electron shell of an atom.
Who developed the "Plum Pudding" Model of an Atom?
J.J Thomson
Write Cl-23 in standard form.
2317Cl
In the periodic table, which group or family of elements has only one valence electron in its outer shell?
The alkali metals
Atomic Number represents the number of _____ in an atom.
Protons
How many Valence Electrons does Oxygen have?
6
Who discovered the nucleus using the famous gold foil experiment?
Ernest Rutherford
The most common form of hydrogen is hydrogen-1. An atom of hydrogen-1 has 1 proton, 0 neutrons, and 1 electron. Hydrogen-3 is an isotope of hydrogen. What subatomic particles make up an atom of hydrogen-3?
1 proton, 2 neutrons, and 1 electron
Which two elements have similar chemical properties according to the periodic table?
helium and argon
An element has 32 protons and 40 neutrons in its nucleus. What is the element?
Germanium (Ge)
Draw the Bohr Model for Argon
What was wrong with Niels Bohr's model of the atom?
It suggested that electrons move in fixed energy levels.
An isotope of chlorine has 17 protons and 18 neutrons. What is the mass number (atomic mass) for the isotope of chlorine?
Cl-35
The elements oxygen (O), sulfur (S), and selenium (Se) are all located in column 16 of the periodic table. What would be true about these elements?
They all have the same number of valence electrons.
T or F: Electrons are found inside the nucleus
False
Who is the Bohr Model Named after?
Niels Bohr
Greek Philosopher that theorized that all material bodies are made up of indivisibly small “atoms.”
Democritus
List the Protons, electrons, neutrons, mass number, and atomic number for the following isotope:
Cr-63
Which of the following is NOT a property of cobalt (Co)?
A. Ductile
B. Malleable
C. 4 Energy levels
D. inert (non-reactive)
D. inert (non-reactive)
What is the difference in atomic mass and mass number?
mass number represents the total count of protons and neutrons in a single atom (always a whole number), while atomic mass is the average mass of all naturally occurring isotopes of an element
Why is the Bohr Model of the atom considered to be an inaccurate diagram of an atom?
The Bohr model portrays electrons as particles orbiting in fixed circular paths, which is not supported by quantum mechanics that describes electrons as wave-like particles with uncertain positions.