Science 1st quarter

What is matter?

Matter occupies space and has mass, and is filled with atoms.

What are protons?

Protons are positively charged particles found in the nucleus of an atom.

What is the atomic number?

The atomic number is the number of protons in an atom, which is also equal to the number of electrons.

Who was Democritus?

Democritus was a Greek philosopher who introduced the concept of the 'atom,' meaning 'uncuttable' or 'indivisible.'

What is the significance of John Dalton in atomic theory?

John Dalton proposed that atoms are tiny, solid balls and created the first modern atomic theory.

What did J.J. Thomson discover?

J.J. Thomson discovered electrons and created the 'plum pudding' model of the atom.

What did Ernest Rutherford contribute to atomic theory?

Ernest Rutherford discovered the nucleus of the atom and showed that atoms are mostly empty space.

How did Niels Bohr describe electron movement?

Niels Bohr proposed that electrons move in fixed orbits around the nucleus.

What is the main distinction between groups and periods in the periodic table?

Groups are vertical columns that share the same number of valence electrons, while periods are horizontal rows that indicate the number of energy levels.

What are valence electrons?

Valence electrons are the electrons in the outermost shell of an atom that determine its chemical reactivity.

What is the Octet Rule?

The Octet Rule states that atoms tend to gain, lose, or share electrons to achieve a full set of eight valence electrons, making them stable.

What defines an ionic bond?

An ionic bond is formed through the transfer of electrons between a metal and a nonmetal.

What is a covalent bond?

A covalent bond involves the sharing of electron pairs between nonmetal atoms.

What is meant by the percentage composition?

Percentage composition shows the percent by mass of each element in a compound.

What is the empirical formula?

The empirical formula represents the simplest whole-number ratio of atoms in a compound.

What is the difference between an empirical formula and a molecular formula?

The empirical formula is the simplest ratio of atoms, while the molecular formula gives the actual number of atoms in a molecule.

What is Lewis Electron Dot Structure (LEDS)?

LEDS consists of an element symbol with dots around it representing valence electrons.

What is the purpose of prefixes when naming covalent compounds?

Prefixes denote the number of each type of atom in covalent compounds, letting us specify the number of atoms present.

What type of bond involves gained or lost electrons?

Ionic bonds involve the gaining or losing of electrons to form charged ions.

Explain Hund's Rule in electron configuration.

Hund's Rule states that electrons fill orbitals one at a time before pairing in sublevels.