Chapter 2 Flashcards
Atom
Basic unit of an element that can enter into chemical combination
Radiation
The emission and transmission of energy through space in the form of waves
Electrons
Negatively charged particles
Radioactivity
Spontaneous emission of particles and/or radiation
Alpha
Positively charged particles (deflected by positively charged plates)
Beta rays
These are electrons and are deflected by negatively charged plates
Gamma rays
Like x rays. Have no charge and are not affected by an external field
Protons
Positively Charged particles in the nucleus
Neutrons
Electrically neutral particles having a mass slightly greater than that of protons
Atomic number
The number of protons in the nucleus of each atom of an electron
In a neutral atom, the number of electrons and neutrons are equal (so atomic number is the same number as well)
Mass number
Total number of neutrons and protons present in the nucleus of an atom of an element
Isotopes
Atoms that have the same atomic number but different mass numbers
Molecule
Aggregate of at least two atoms in a definite arrangement held together by chemical forces (aka a chemical bond)
Polyatomic molecules
Molecules containing more than two atoms
Like H2O and ammonia (NH3)
Chemical formulas
Expresses the composition of molecules and ionic compounds in terms of chemical symbols
Molecular formula
Shows the exact number of atoms of each element in the smallest unit of a substance
Allotrope
This is one of two or more distinct forms of an element
Organic vs inorganic compounds
Organic contain carbon with some kind of other element like hydrogen, oxygen, nitrogen and sulfur
Compounds
Composed of atoms of more than one element
A chemical reaction
Separation, combination or rearrangement of atoms (but neither created nor destroyed here)
Atomic number
Number of protons in nucleus
Isotopes
Atoms of the same element with different numbers of neutrons
Proust’s Lw of definite proportions
chemical compound always contains its component elements in fixed ratio (doesnt matter how the sample was obtained)
Law of multiple proportions
Ratios of small whole numbers in masses of compounds