Vocabulary
Chemical Bond
attractive force between atoms or ions that binds them together as a unit
Positive ions are
smaller than the neutral atom from which they are formed
Negative ions are
larger than the neutral atom from which they are formed
The three classes of elements
1. Metals
2. Non-metals
3. Metalloids
The Periodic Law
states that the physical and chemical properties of the elements are periodic functions of their atomic numbers
Covalent bonding
electrons are shared between atoms in a molecule or in polyatomic ions
The increased positive charge of the nucleus pulls
electrons in closer
The extra repulsion produced from the additional electrons cause
the ion to expand
Metal
Elements containing atoms that readily lose electrons to form positive ions
Valence Electrons
electrons found in the outermost energy level of atoms
Polar Covalent
an uneven sharing of electron—resulting in an asymmetrical electron density
The resulting cation is
smaller than the neutral atom
The resulting anion is
larger than the neutral atom
Non-metal
Elements containing atoms that readily gain electrons to form negative ions
Dmitri Mendeleev
A Russian chemist, who was the first to publish a system of classifying elements, in 1869
Non-Polar Covalent
an even sharing of electron-resulting in an symmetrical electron density
Valence electrons are
Removed
Valence electrons are
Added
Metalloid
In between metals and nonmetals
Henry Moseley
An English scientist that discovered the elements fit into patterns better when they were arranged according to atomic number, rather than atomic mass
Ionic bonding
positively and negatively charged ions are held together by electrostatic forces electrons are transferred
More protons than electrons causes the nucleus to
pull in electrons closer
More electrons than protons causes
the ion to expand due to increased repulsive forces
T/F Metal is a more common element than the other 2
True
How many elements are there
There are 92 naturally occurring elements