Video Notes: Cosmology, Big Bang, Atomic Theory, and Biomolecules

A comprehensive set of Q&A flashcards covering cosmology, Big Bang evidence and timeline, star formation and life cycle, atomic structure, molecular polarity, periodic trends, and biomolecules based on the provided notes.

What is cosmology?

The study of how the universe began, how it continues to exist, and how it will end.

What is the Big Bang Theory?

The scientific explanation that the universe began from an explosion of a very small, hot, and dense point about 13.8 billion years ago.

Who proposed the original idea that the universe is expanding in 1927?

Georges Lemaître, the Father of the Big Bang Theory.

Which American astronomer discovered that galaxies are moving away, supporting the expansion of the universe?

Edwin Hubble.

What did Einstein call the cosmological constant after accepting the expanding universe idea?

His “biggest blunder,” which he introduced to keep the universe static.

Who predicted the cosmic microwave background radiation (CMB) in the 1940s?

George Gamow (with his students).

Who accidentally discovered the CMB in 1965?

Arno Penzias and Robert Wilson.

What is the cosmic microwave background radiation (CMB)?

Leftover heat from the Big Bang now cooled and spread throughout the universe.

What are the four major evidences of the Big Bang?

CMB, redshift of galaxies, abundance of light elements, and large-scale structure of the universe.

What does the redshift of distant galaxies indicate?

Galaxies are moving away, meaning the universe is expanding and began from a very small point.

What elements are predicted by Big Bang nucleosynthesis?

Hydrogen, helium, and a small amount of lithium.

What does the Large-Scale Structure of the Universe show?

Patterns of galaxy distribution that fit with matter clumping after the Big Bang.

In the Big Bang timeline, what happened at time 0 seconds?

The Big Bang; the universe begins; time and space start.

What is inflation in the Big Bang timeline?

A period of extremely fast expansion that smooths and flattens space and cools the temperature.

What happened at about 3 minutes after the Big Bang?

Nucleosynthesis: protons and neutrons form nuclei.

What happened around 380,000 years after the Big Bang?

Recombination: electrons join nuclei and light is released.

When did the first stars form according to the timeline?

Approximately 400 million years after the explosion.

When did galaxies and large structures begin to form?

About 1 billion years after the Big Bang.

When did our solar system form according to the timeline?

About 9 billion years after the Big Bang (the Sun and Earth formed ~4.6 billion years ago).

What is the current era in the Big Bang timeline?

Today – the universe continues to expand and evolve.

What is nuclear fusion?

The process where two light atomic nuclei combine to form a heavier nucleus.

What is a star as defined in these notes?

A luminous celestial body composed mostly of hydrogen and helium, generating energy through nuclear fusion in its core.

When was the first star formed according to the notes?

400 million years after the Big Bang.

What is stellar nucleosynthesis?

The process by which elements are formed inside stars through nuclear fusion.

What is the typical composition of a star?

About 70-75% hydrogen, 24-28% helium, and ~2% heavy elements (C, O, N, Fe, etc.).

What is the octet rule?

Atoms tend to gain, lose, or share electrons to have eight electrons in their valence shell, achieving stability like noble gases.

What is polarity in molecules?

The equal or unequal sharing of electrons among the atoms of a molecule.

What are polar molecules?

Molecules in which electrons are shared unequally.

What are non-polar molecules?

Molecules in which electrons are shared equally.

What is electronegativity?

The ability of an atom to attract electrons toward itself when bonded to another atom.

How does electronegativity vary across a period and up a group?

Increases across a period (left to right) and increases up a group (toward the top).

What is electron configuration?

The arrangement of electrons in the orbitals of an atom; shows how many electrons are in each energy level and sublevel.

What are the meanings of Group and Period in the periodic table?

Group is a vertical column; Period is a horizontal row.

What are the chromium and copper electron configuration exceptions?

Chromium (Cr, Z=24) is stabilized by a half-filled 3d subshell; Copper (Cu, Z=29) is stabilized by a fully filled 3d subshell.

Who discovered phosphorus, and when?

Hennig Brand in 1669.

What is the meaning of the name phosphorus?

From Greek phōs (light) and phoros (bearer) — “light-bearer” because it glows.

Which element is the most recently discovered real element?

Oganesson (Og).

What is alchemy?

An early mix of science and mysticism focused on transformation.

Who is an alchemist?

A person who practiced alchemy.

What is the origin of the word atom?

From the Greek atomos meaning indivisible.

What are the three basic subatomic particles and where are they located?

Protons (positively charged, in the nucleus), Neutrons (neutral, in the nucleus), Electrons (negatively charged, in shells around the nucleus).

Which shapes are associated with polar and non-polar molecules?

Polar: Bent, Trigonal Pyramidal, Seesaw, T-shaped. Non-polar: Linear, Trigonal Planar, Trigonal Bipyramidal, Tetrahedral, Octahedral, Square Planar.

Which scientist proposed the Plum Pudding model of the atom?

J. J. Thomson.

What experiment led Rutherford to propose the Nuclear Model of the atom?

The Gold Foil Experiment.

Who conducted the cathode ray tube experiment and what did it discover?

J. J. Thomson discovered the electron.

What did James Chadwick discover?

The neutron.

What are the stages in the short star life cycle flow chart?

Birth of a Star (Nebula), Protostar, Stellar Life (Main Sequence).