Energy Level
What is the name of the region around the nucleus where electrons are most likely to be found?
An energy level or electron shell.
What is the electron configuration of hydrogen (atomic number 1)?
1s¹
What is the purpose of using noble gas shorthand in electron configurations?
To simplify long electron configurations
What symbols are used to represent electrons in orbital notation?
Arrows (↑ and ↓).
What is observed during a flame test?
The color of the flame changing
What is the maximum number of electrons that can fit in one orbital?
2 electrons
Write the full electron configuration for oxygen (atomic number 8).
1s² 2s² 2p⁴
What is the noble gas configuration for sodium (Na, atomic number 11)?
[Ne] 3s¹
What does one box in orbital notation represent?
One orbital
Why do different elements produce different flame colors?
Because their electrons release specific amounts of energy when returning to lower levels
How many subshells are in the second energy level, and what are they called?
Two subshells: 2s and 2p.
What does an electron configuration show?
The arrangement of electrons in an atom’s orbitals.
What is the noble gas configuration for chlorine (Cl, atomic number 17)?
[Ne] 3s² 3p⁵
Draw the orbital notation for carbon (atomic number 6).
1s ↑↓
2s ↑↓
2p ↑ ↑
What color does sodium produce in a flame test?
Yellow
List the number of orbitals in the s, p, d, and f subshells.
s = 1, p = 3, d = 5, f = 7.
Why do electrons fill the 1s orbital before the 2s orbital?
Because the 1s orbital is lower in energy and electrons fill the lowest available energy levels first.
Why are noble gases used as the reference point in shorthand electron configuration?
They have full outer shells, representing a stable electron configuration.
In orbital notation, how do you show that an orbital has two electrons?
By drawing two arrows in the same box: one pointing up (↑) and one pointing down (↓).
Describe the energy change that occurs during a flame test.
Electrons absorb energy, jump to higher levels, and then release energy as visible light when they fall back.
Explain how energy levels, subshells, and orbitals relate to one another in the structure of an atom.
Energy levels contain subshells (s, p, d, f), which are made up of orbitals that each hold two electrons; this layered system explains electron arrangement and chemical behavior.
What is the full electron configuration for magnesium (atomic number 12), and how does it relate to its position on the periodic table?
1s² 2s² 2p⁶ 3s²
Magnesium is in period 3 and group 2, which matches the 3s² outer shell configuration.
How does noble gas configuration help predict the reactivity of elements in the same group as the noble gas?
It shows how close an element is to achieving a full outer shell—elements that only need to gain or lose a few electrons to match a noble gas configuration are highly reactive.
Draw the orbital notation for nitrogen (atomic number 7).
1s ↑↓
2s ↑↓
2p ↑ ↑ ↑
How can the flame test be used to identify unknown metal ions, and what is a limitation of this method?
Each metal emits a unique flame color, which helps identify it, but it may be ineffective if multiple metals are present.