Atomic Foundations
Navigating the Periodic Table
Elemental Families
The World of Ions
Chemical Calculations
100

This is the fundamental, smallest unit of an element that retains all the chemical properties of that element.

What is an atom?

100

Dmitri Mendeleev is credited with organizing elements into this iconic tabular arrangement based on their repeating chemical and physical properties.

What is the periodic table?

100

Making up the vast majority of the periodic table, this broad class of elements is characterized by high electrical conductivity, shiny luster and malleable properties.

What is a metal?

100

This specific ion carries a positive charge because the neutral atoms lost one or more electrons.

What is a cation?

100

This fundamental chemical rule states that atoms tend to gain, lose, or share electrons to achieve a stable arrangement of eight outer electrons.

What is the octet rule?

200

This specific number, uniques to every element, represents the number of protons found in an atoms nucleus.

What is the atomic number?

200

These are the vertical columns on the periodic table, whose elements share similar chemical characteristics.

What are groups or families?

200

Found in Group 18, this specific family of non-reactive elements features a naturally complete outer electron shell.

What are noble gases?

200

When an atom of Group 1 metal reacts to become stable, it forms a cation with this specific numerical charge.

What is +1?

200

A neutral atom of Carbon-14 has an atomic number of 6. This is the exact number of neutrons found in its nucleus

What is 8?

300

Atoms of the same element that contain identical numbers of protons but differing number of neutrons.

What are isotopes?

300

This term refers to the horizontal rows across the periodic table, representing the number of electron shells an element's atom possess.

What are periods?
300

This chemical family consists of reactive metals that typically lose two electrons to become stable.

What are Alkaline Earth Metals?

300

The specific type of ion that carries a negative charge because the neutral atom gained one or more electrons.

What is an anion?

300

An atom of Aluminum has an atomic number of 13 and a mass number of 27. It loses 3 electrons to form an Aluminum ion. This is the number of remaining electrons.

What is 10?

400

This theory proposed that all matter is made of indivisible atoms, and that all atoms of a given element are completely identical in mass and properties.

What is Dalton's Atomic Theory?

400

These elements occupy a jagged zig-zag line on the periodic table, displaying an intermediate blend of both metallic and nonmetallic characteristics.

What are metalloids?

400

This is the specific number of valence electrons naturally found in a neutral atom of any Group 14 element.

What is four?

400

These electrons are found in the outermost energy level of an atom.

What are valence electrons?

400

Chlorine has an atomic number of 17. Based on its position in Group 17, this is the number of valence electrons a neutral chlorine atom possesses.

What is 7?

500

When two or more atoms are chemically bound together by sharing or transferring electrons, they form this neutral chemical structure/

What is a molecule?

500

This element has eight valence electrons and an atomic mass of 40.

What is Argon?

500

These are found in the nucleus of atom.

What are protons and neutrons?

500

This specific type of chemical bond is formed when two nonmetal atoms physically share pairs of valence electrons to achieve stability.

What is a covalent bond?

500

An isotope of Uranium has 92 protons and 146 neutrons. This is the overall mass number of this specific isotope.

What is 238?

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