Module 3 - Atoms, Molecules, and Ions Flashcards
Who formed a theory about atoms?
John Dalton
What are the main postulates of Dalton’s atomic theory?
- All matter is composed of tiny, indivisible particles called atoms.
- All atoms of a specific element are identical in mass, size, and other properties. (However, atoms of different elements exhibit different properties and vary in mass and size.)
- Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller particles.
- Atoms of different elements can combine in fixed whole-number ratios to form compounds.
- Atoms can be rearranged, combined, or separated in chemical reactions.
What was the reason why Dalton’s atomic theory had to be modified?
The discovery of subatomic particles and isotopes.
Law of matter that refers to the total mass of substances present after a chemical reaction is the same as the total mass of substances before the reaction.
Law of conservation of mass
Law of matter that refers to all samples of a compound have the same composition—the same proportions by mass of the constituent elements.
Law of constant composition
It is the fundamental building
block of all matter and chemistry.
Atoms
A subatomic particle that is a small negatively charged particles that orbit around an atom’s positively charged nucleus.
Electrons
A subatomic particle that is a smaller bit of positively charged matter or sub-atomic particle within the nucleus.
Protons
The mass of a proton is _____ times greater than an electron
1800
A subatomic particle that refers to the particles located inside the nucleus with a similar mass to their partner proton but with no electrical charge.
Neutrons
Defined as the total number of protons and neutrons in an atom.
Mass number
_______ are composed of atoms chemically bonded by attractive forces.
Molecules
These are the elements that occur naturally in pairs or as two-atoms.
Diatomic molecules
Refers to the force that binds two or more atoms together.
Chemical bond
A bond wherein electrons are shared equally.
Covalent bond
A bond when electrons are transferred from one atom to another.
Ionic bond
A bond that is formed between two non-metals that have similar electronegativities.
Covalent bond
A bond that is formed between a metal and a non-metal.
Ionic bond
A formula that gives the exact number of atoms of each element in a molecule.
Molecular formula
A formula that shows how specific atoms are ordered and arranged in compounds. It makes it easier to see how atoms are bonded.
Structural formula
These are the atoms that lose or gain electrons. Atoms are electrically neutral or uncharged.
Ions
Positively charged ion
Cation
Negatively charged ion
Anion
