Chemistry Class Questions on Atoms

The central part of an atom containing protons and neutrons.

Negatively charged particles that orbit the nucleus in shells.

The number of protons in an atom's nucleus.

The total number of protons and neutrons in an atom's nucleus.

Energy levels around the nucleus where electrons reside.

A substance composed of only one type of atom. Examples include gold (Au) and oxygen (O).

A substance formed when two or more different elements combine chemically in a fixed ratio. Examples include water (H2O) and salt (NaCl).

An atom or molecule with an electrical charge, caused by gaining or losing electrons.

A chemical bond formed by the sharing of electrons between two atoms.

A chemical bond formed by the electrostatic attraction between oppositely charged ions.

A negatively charged ion consisting of one oxygen atom and one hydrogen atom. Often seen in bases and alkaline solutions.

A negatively charged ion consisting of one carbon atom and three oxygen atoms. Often found in salts like baking soda.

A negatively charged ion consisting of one nitrogen atom and three oxygen atoms. A common component of fertilizers.

A negatively charged ion consisting of one sulfur atom and four oxygen atoms. Often found in minerals like gypsum.

In this process, chemical equations are balanced by ensuring that the number of atoms of each element on the reactants' side matches the number on the products' side.

A group of atomic orbitals with the same principal quantum number. It represents the energy level of electrons.

A subgroup of orbitals within an electron shell, characterized by the same type of orbital (s, p, d, or f). For example, the 2nd shell has a 2s and a 2p subshell.

A region of space within an atom where there is a high probability of finding an electron. Each orbital can hold a maximum of 2 electrons.

The 3rd electron shell can hold up to 18 electrons, but its maximum capacity is dependent on the number of protons in the nucleus.

Atomic orbitals are categorized into four types: s, p, d, and f, each with a specific shape and energy level.

The number of orbitals in an electron shell increases with the shell number. The first shell (n=1) has one s orbital. The second shell (n=2) has one s orbital and three p orbitals. The third shell (n=3) has one s orbital, three p orbitals, and five d orbitals.

The order in which electrons fill orbitals follows a specific pattern. This pattern is called the Aufbau principle, which states that electrons fill orbitals in increasing order of energy.

Each orbital holds a maximum of two electrons, with opposite spins.

The number of moles of a substance is equal to the mass of the substance divided by its molar mass (Mr).

Molarity is a measure of the concentration of a solution. It is calculated by dividing the number of moles of the solute by the volume of the solution in cubic decimeters (dm³).

A dilute solution has a lower concentration of solute compared to a concentrated solution.

100 cubic centimeters (cm³) is equivalent to 10 cubic decimeters (dm³).

The number of electrons in an atom is equal to the number of protons. This number is called the atomic number.

A cell that lacks a nucleus and other membrane-bound organelles. Its genetic material is located within the cytoplasm.

A cell that contains a nucleus and other membrane-bound organelles. Their genetic material is contained within the nucleus.

Structures within a cell that perform specific functions. Examples: nucleus, ribosomes, mitochondria.

A complex of DNA and proteins found within the nucleus of eukaryotic cells, responsible for storing genetic information.

In eukaryotic cells, the nucleus is a membrane-bound compartment that contains the cell's genetic material (DNA).

A region of space around the nucleus of an atom where an electron is likely to be found.

The first energy level in an atom, containing only one s sub-shell.

A group of orbitals with similar energy levels. For example, the second shell consists of one s sub-shell and three p sub-shells.

A sub-shell that can hold up to two electrons.

A sub-shell that can hold up to six electrons. It consists of three orbitals, often referred to as px, py, and pz.

Atoms joined together by covalent bonds. They are the smallest unit of a substance that can exist independently.

A type of covalent bond where two atoms share two pairs of electrons.

A type of covalent bond where two atoms share one pair of electrons.

Two or more atoms held together by covalent bonds.

Ionic compounds conduct electricity when melted or dissolved because the ions are free to move.

Magnesium oxide is an ionic compound with stronger bonds than others. This is because Mg has an extra electron which leads to stronger attraction.

Solid ionic compounds form a repeating pattern of ions in a 3-dimensional lattice. Opposite charges always attract and fit together tightly.

Ionic compounds are essential for life. Without them, we wouldn't have common acids and bases.

Common salt is a vital ionic compound. It is used in our daily lives for flavoring foods, preserving food, and other purposes.