Periodic Table: History, Properties, and Electron Configuration of Elements

Who was the first to attempt grouping elements into metals and nonmetals?

Antoine Lavoisier in 1789.

What classification system did J. W. Dobereiner publish in 1829?

He grouped elements into triads based on similar properties.

What significant event in chemistry occurred in Karlsruhe, Germany, in 1860?

The first international conference of chemistry.

Who arranged about 62 elements into a periodic table based on atomic mass in the 1860s?

John Newlands.

What was a major flaw in John Newlands' periodic table?

He did not allow gaps for undiscovered elements.

Who published a more successful periodic table and predicted properties of undiscovered elements?

Dmitri Mendeleev.

How did Mendeleev arrange the elements in his periodic table?

By atomic mass while prioritizing similar properties in columns (groups).

What inspired Mendeleev to create the periodic table?

He was inspired by a dream and the card game solitaire.

What does the term 'periodic' refer to in the periodic table?

The repeating properties of elements at regular intervals.

What are the general properties of nonmetals?

Poor conductors of heat and electricity, brittle if solid, non-ductile, and can be solids, liquids, or gases at room temperature.

What is a metalloid?

An element that has properties similar to both metals and nonmetals.

What are the conditions under which metalloids can behave like metals or nonmetals?

Their behavior can change with temperature, pressure, or by adding different elements.

What are the noble gases known for?

They are inert gases that rarely take part in reactions.

Which noble gas is the third most abundant in our atmosphere?

Argon.

What are the two rows of inner transition metals called?

Lanthanides (top row) and Actinides (bottom row).

What is the quantum mechanical model of the atom?

A model that describes electrons in terms of energy levels and probability clouds rather than fixed orbits.

What are atomic orbitals?

Regions of space where there is a high probability of finding electrons.

What shapes are atomic orbitals labeled as?

s, p, d, or f orbitals.

What is the significance of energy levels in an atom?

They represent fixed energies that electrons can have.

What did Erwin Schrödinger contribute to atomic theory?

He used math to describe the behavior of electrons in the quantum mechanical model.

What is the maximum number of electrons an orbital can hold?

Up to 2 electrons

What is used to describe the location of electrons in orbitals?

Electron configurations

What principle states that an atomic orbital may have at most two electrons with opposite spins?

Pauli exclusion principle

What do we call the electrons in the highest occupied energy level of an atom?

Valence electrons

What does the Aufbau principle state about filling orbitals?

Easier orbitals and energy levels fill up first.

What does Hund's rule state about electron occupancy in orbitals?

Each orbital gets one electron first before adding a second.

What is the significance of valence electrons in determining reactivity?

They determine how likely an element is to form a compound.

What is the periodic law?

When elements are arranged by increasing atomic number, their physical and chemical properties show a periodic repetition.

What are the properties of metals?

Good conductors of heat and electricity, malleable, ductile, possess metallic luster, and solid at room temperature (except Hg).

What are the properties of nonmetals?

Poor conductors of heat and electricity, brittle if solid, non-ductile, and can be solids, liquids, or gases at room temperature.

What are metalloids?

Elements that have properties similar to both metals and nonmetals and can behave like either under certain conditions.

What are noble gases known for?

They are inert gases that rarely participate in reactions.

Who was the scientist that proposed the quantum mechanical model of the atom?

Erwin Schrödinger

What is the difference between orbitals and orbits?

Orbitals are regions of probability for electron location, while orbits suggest a fixed path.

What is the significance of the number of rows (periods) in the periodic table?

There are 7 rows, each corresponding to a principal energy level.

What does the term 'metallic luster' refer to?

The shiny appearance characteristic of metals.

What happens to the properties of elements across a period?

They become less metallic and more nonmetallic.

What is the role of electrons in determining the properties of elements?

Electrons play a key role in defining an element's chemical properties and reactivity.