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Review Atoms are the basic building units of matter around us. An atom consists of three basic particles: positively charged protons, negatively charged electrons and neutral neurons. Electrons revolve around the nucleus. The nucleus is at the center of the atom and consists of protons and neutrons. The pathway of electrons around the nucleus is called orbit. An atom is neutral due to equal number of electrons in the orbits and number of protons in the nucleus.
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Ions (Cations & Anions) Bohr Diagrams Lewis Dot
Diagrams
Science 10 Ions (Cations & Anions) Bohr Diagrams Lewis Dot
Diagrams Review Atoms are the basic building units of matter around
us.
An atom consists of three basic particles: positively charged
protons, negatively charged electrons and neutral neurons.
Electrons revolve around the nucleus. The nucleus is at the center
of the atom and consists of protons and neutrons. The pathway of
electrons around the nucleus is called orbit. An atom is neutral
due to equal number of electrons in the orbits and number of
protons in the nucleus. Words To Know Ion An atom, or group of
atoms, that has a net positive or negative charge. Cation An ion
with a net positive charge, due to the loss of one or more
electrons from a neutral atom. Usually formed by metals. Example:
Sodium atom, Na, can readily lose an electron to become a sodium
cation, Na+ Anion An ion whose net charge is negative due to an
increase in the number of electrons. Usually formed by non-metals.
Example: Chlorine atom, Cl, can gain an electron to become a
chloride ion, Cl- Monatomic Ion Contains only one atom, such as
Fe3+, Mg2+ Polyatomic/Molecular Ion - Two or more atoms can combine
to form an ion that has a net positive or negative charge, such as
OH-, NH4+ Examples A sodium atom, Na, whose atomic number is 11,
has 1 electron in its valence shell, surrounding inner shells with
2 and 8 electrons. A sodium atom loses its extra becoming a cation.
Na > Na+ + e- A chlorine atom, Cl, whose atomic number is 17,
has 7 electrons in its valence shell. Thus a chlorine atom gains an
electron to attain a stable configuration with 8 electrons in
valence shell. Chlorine forms an anion in this process. Cl + e-
> Cl- Valence Shell: The outer shell of the atom. Electrons form
a 2, 8, 8, etc arrangement around shells; the electrons that occupy
the valence shell are called valence electrons. Bohr Diagrams A
Bohr diagram is a simplified visual representation of an atom that
was developed by Danish physicist Niels Bohr in The diagram depicts
the atom as a positively charged nucleus surrounded by electrons
that travel in circular orbits about the nucleus in discrete energy
levels. Rules For Drawing Bohr Diagrams
Consult the Periodic Table of the Elements for the type of atom you
are going to represent in a Bohr diagram. Write down its atomic
number and mass number. The atomic number is the number of protons,
and the mass number is the number of protons and neutrons. The
number of electrons is equal to the number of protons. See which
row of the Periodic Table your element is in. Elements in the first
row (hydrogen and helium) have one energy level, those in the
second row will have two energy levels and so on. Draw a circle to
represent the nucleus of the atom. Write the number of protons and
the number of neutrons inside this circle. Draw one or more circles
around the nucleus depending on which row of the Periodic Table
your element comes from. Each ring represents a different energy
level for the electrons. Rules For Drawing Bohr Diagrams
Draw electrons as dots on the rings that represent the energy
levels. Each ring has a maximum number of electrons that it can
hold. The first (inner) ring can only hold 2 electrons, the second
level can hold 8, the third can hold 8 and the fourth holds 8. Bohr
Diagram Which ion is this? Electron Dot Diagrams American chemist
Gilbert Lewis invented electron dot diagrams to help him understand
and predict the bonding that occurs between atoms. Also called
Lewis diagrams, they represent the atom of an element by showing
only the outer valence electrons and the chemical symbol. Electron
Dot Diagrams Electron Dot Diagrams
Electron dots representing electrons are placed around the element
symbol at the points of a compass (North, South, East & West).
Electron dots are placed singly first until the 5th electron is
reached; at this point the electrons are then paired. Pairs of
electrons in Electron Dot Diagrams are called Lone Pairs. Single
electrons in Electron Dot Diagrams are called Bonding Electrons,
because they are looking for another electron to make a pair (bond)
with.