Periodic Table Basics
What is the total number of periods (rows) in the periodic table?
7
What type of element is Sodium (Na)?
Metal
What happens to atomic radius as you move left to right across a period?
It decreases
EXPLANATION: As you move from left to right across a period, more protons are added to the nucleus of the atom. This increases the nuclear charge (positive charge in the nucleus), which pulls the electrons closer to the nucleus. Since the number of energy levels (or shells) remains the same, this stronger attraction causes the size of the atom (atomic radius) to decrease.
Which element is in Period 2, Group 16?
Oxygen (O)
What is the most reactive metal?
Francium (Fr), but Cesium (Cs) is commonly accepted due to its availability
What is the total number of groups (columns/families) in the periodic table?
18
What type of element is Oxygen (O)?
Nonmetal
What happens to atomic radius as you move down a group?
It increases
EXPLANATION: As you move down a group in the periodic table, new energy levels (or shells) are added to the atom. Each additional energy level increases the distance between the outermost electrons and the nucleus, which results in a larger atomic radius. Although the nuclear charge increases, the shielding effect (inner electrons blocking the attraction between the nucleus and outer electrons) reduces the pull on the outermost electrons, allowing the atom to expand.
How many valence electrons does Neon (Ne) have?
8
What is the most reactive nonmetal?
Fluorine (F)
What do all elements in the same group have in common?
Same number of valence electrons
What is a metalloid?
An element that has properties of both metals and nonmetals
Define ionization energy.
The energy required to remove an electron from an atom
Which element is located in Group 1, Period 4?
Potassium (K)
How did Henry Moseley improve the periodic table?
He arranged it by atomic number instead of atomic mass
What do all elements in the same period have in common?
Same number of energy levels
Name two elements that are liquids at room temperature.
Mercury (Hg) and Bromine (Br)
Which element has the highest electronegativity?
Fluorine (F)
Identify this element: It has 6 protons, is a solid, and is found in all living things.
Carbon (C)
Explain why noble gases do not form bonds easily.
They have a full outer shell of valence electrons, making them stable
Who is known as the “Father of the Periodic Table”?
Dmitri Mendeleev
Which group contains only nonmetals?
Group 18 - Noble Gases
Why does ionization energy increase across a period?
More protons create a stronger nuclear attraction, making it harder to remove electrons
Identify this element: It is a noble gas with an atomic number of 10.
Neon (Ne)
Explain why elements in Group 1 (Alkali Metals) are highly reactive.
Elements in Group 1, known as Alkali Metals, are highly reactive because they have one valence electron in their outermost energy level. This single electron is easily lost during a reaction to achieve a stable, full outer energy level (a noble gas configuration). The lower the ionization energy (which decreases as you move down the group), the easier it is for the atom to lose this electron, increasing reactivity.