Lecture 3_8-26-25 Subatomic Particles, Perioidic Table, Energy File

Flashcards covering atomic structure, subatomic particles, isotopes, ions, the periodic table's organization, properties of element groups, and fundamental concepts of energy and Coulomb's Law.

Neutron

A subatomic particle with an approximate mass of 1 amu.

Proton

A subatomic particle with an approximate mass of 1 amu.

Electron

A subatomic particle with an approximate mass of ~0 amu.

Subatomic particles

The different number of these particles (protons, neutrons, electrons) makes atoms different.

Atomic number

The number of protons in an atom, which characterizes the element.

Mass number

The total number of protons and neutrons in an atom.

Isotopes

Atoms of the same element (same atomic number and number of protons) but with different mass numbers (different number of neutrons).

Atomic mass

A weighted average of all the isotopes of an element, taking into account their percent relative abundance.

Neutral atom

An atom where the number of protons equals the number of electrons.

Anion

An atom where the number of protons is less than the number of electrons (a negatively charged ion).

Cation

An atom where the number of protons is greater than the number of electrons (a positively charged ion).

Ion charge

Calculated as the number of protons minus the number of electrons.

Dmitri Mendeleev’s Periodic Table

Organized by both mass and reactivity, and famously predicted the existence of 'missing elements' before their discovery.

Group (column)

A vertical column on the periodic table, indicating elements with similar chemical properties.

Period (row)

A horizontal row on the periodic table.

Metals

Elements that generally lose electrons easily, found on the left and center of the periodic table.

Non-metals

Elements that generally gain electrons easily (with noble gases as an exception), found on the upper right of the periodic table.

Metalloids

Elements that possess characteristics of both metals and non-metals, located along the staircase line on the periodic table.

Noble Gases

Elements in Group 8A, known for being fairly unreactive and existing as gases at room temperature.

Halogens

Elements in Group 7A, which very easily gain 1 electron.

Alkali Metals

Elements in Group 1A, which are very reactive (reactivity increases down the group), malleable, ductile, good conductors, and easily lose 1 electron.

Alkaline Earth Metals

Elements in Group 2A, which easily lose 2 electrons.

Transition Metals

Elements in the d-block of the periodic table, which are malleable, good conductors, mostly solids at room temperature, and can lose a varying number of electrons.

Lanthanides

A series of very reactive elements (part of the inner transition metals) that easily lose electrons.

Actinides

A series of radioactive and unstable elements (part of the inner transition metals), most of which can only be made in a laboratory setting.

Reactivity (of elements)

Primarily dictated by the behavior of electrons, which explains the organization of the periodic table.

Energy

The ability to do work, existing as either kinetic or potential energy.

Kinetic energy

Energy due to motion, with the kinetic energy of molecules often measured as temperature.

Potential energy

Energy due to position, stored in molecular bonds and intermolecular forces, or in Coulombic interactions between subatomic particles.

High energy state

A state that is more reactive and less stable.

Low energy state

A state that is less reactive and more stable.

Spontaneous processes

Processes that occur on their own because they release energy.

Coulomb’s Law

States that the energy between two charged particles decreases when charges are opposite, increases when charges are the same, is proportional to the charges, and is inversely proportional to the distance between them (E = q1q2/r).