Moseley's Periodic Law states that the physical and chemical properties of elements are periodic functions of their ___ .

Atomic number

Which group of elements have the same electronic configuration of ns¹, leading to similar properties?

Alkali metals

Identify the general trend in the number of elements present in each period of the periodic table.

The number of elements in each period is twice the number of atomic orbitals available in the energy level being filled.

What is the significance of the noble gases in the periodic table?

Noble gases are chemically inert.

• Full valence shells result.

• Stable configurations established.

• Used in lighting and welding.

Fill in the blank: Iridium is the most dense element, followed by ___.

Osmium

True or False: The last entered electron determines the block of an element in the periodic table.

True

What characterizes the elements in the s-block of the periodic table?

The last entered electron occupies an s orbital.

How many periods are there in the long form of the periodic table?

There are seven periods.

Riddle: I am a gas that is colorless and inert, with eight electrons in my outer shell. What am I?

A noble gas, such as Neon or Argon.

What defines metalloids in the periodic table?

Metalloids have properties intermediate between metals and nonmetals and include elements like Boron, Silicon, and Germanium.

Fill in the blank: The long form of the periodic table is also known as ___ table.

Bohr's

True or False: All elements in the periodic table are classified as metals.

False. There are non-metals and metalloids as well.

What is the primary reason for the periodic properties observed in elements?

Periodic properties arise from the recurrence of similar valence shell electronic configurations at regular intervals.

How many non-metals are there in the periodic table, including hydrogen?

Seventeen non-metals.

Riddle: I am a liquid non-metal at room temperature that belongs to the halogens. What am I?

Bromine (Br).

Explain how the number of elements in the first and third periods differ.

First and third periods differ in element count.

• First period has two elements.

• Third period has eight elements.

• Orbital filling explains the difference.

Identify the two types of non-metals that exist as gases at room temperature.

Monoatomic noble gases and diatomic gases such as H₂, O₂, N₂, and Cl₂.

Fill in the blank: The last element in each period is typically a ___ gas.

Noble

What is the role of the principal quantum number in defining periods of the periodic table?

The principal quantum number corresponds to the energy level of the valence shell, determining which period an element belongs to.

Describe the significance of the Aufbau Principle regarding element classification.

The Aufbau Principle aids classification.

• Determines electron arrangement.

• Defines element block placement.

• Essential for periodic trends.