Inside the Atom
This subatomic particle has a positive charge.
Proton
An oxygen atom has 8 protons. How many electrons does it have?
8 electrons
This term describes the electrons in an atom’s outermost shell.
Valence electrons
This family includes lithium, sodium, and potassium.
Alkali metals
These elements are usually shiny and good conductors of heat and electricity.
Metals
This subatomic particle is found outside the nucleus and has a negative charge.
Electron
A fluorine atom has a mass number of 19 and an atomic number of 9. How many neutrons does it have?
10 neutrons
An atom is in Period 3. How many occupied electron shells does it have?
3 occupied shells
Group 2 elements belong to this family.
Alkaline earth metals
These elements have properties of both metals and nonmetals.
Metalloids
These two types of particles are found in the nucleus.
Protons and neutrons
A boron atom has 5 protons and 6 neutrons. What is its mass number?
11
A neutral carbon atom has 6 electrons. Give the number in each shell, starting with the innermost shell.
2, 4
This family has 7 valence electrons and includes fluorine and chlorine.
Halogens
What does the period number tell you about an atom’s electron arrangement?
The number of occupied electron shells or number of orbits
This number identifies an element and tells you how many protons it has.
Atomic number
An argon atom has an atomic number of 18 and a mass number of 40. Give its numbers of protons, neutrons, and electrons.
18 protons, 22 neutrons, 18 electrons
A neutral neon atom has 10 electrons. Give its electron arrangement and explain why it is very unreactive.
2, 8;
its outer shell is full
This family has full outer electron shells and is the least reactive.
Noble gases
For the main-group elements in your review, what do atoms in the same group generally have in common about their outer electrons?
The same number of valence electrons. Exception: helium has 2, while the other noble gases have 8.
An atom has 16 protons and a mass number of 32. How many neutrons does it have?
16 neutrons
An atom has 19 electrons and 20 neutrons. Identify the element and give its mass number.
Potassium;
mass number 39
A neutral phosphorus atom has 15 electrons. Give its electron arrangement and number of valence electrons.
2, 8, 5;
5 valence electrons
Explain why alkali metals are highly reactive using their valence electrons.
They have one valence electron that is easily lost during reactions.
Name all eight elements in Period 3, in order from left to right.
Sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon