7.4 Using the Bohr Theory
BOHR DIAGRAMS Practice (worksheet)
Draw Bohr Diagrams for:
hydrogen
sodium
phosphorus
neon
calcium
First shell: 2 electrons
Second shell: 8 electrons
Fourth shell: 8 electrons
Third shell: 8 electrons
•When a neutral atom gains or loses electrons
BOHR DIAGRAMS for Ions
NEUTRAL ATOM
ION
How many electron(s)?
How many electron(s)?
How many protons?
How many protons?
OVERAL charge?
OVERAL charge?
Patterns of Electron Arrangement in Groups
Which group has a STABLE OCTET in its outer most
shell?
If there are 8 electrons in the last shell = STABLE OCTET
1 exception = HELIUM (2 electrons)
ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!!
All ATOMS want to be
like
NOBLE GASES!
If there are 8 electrons in a shell = STABLE OCTET
Valence Shell = OUTERMOST SHELL
VALENCE ELECTRONS
Electrons in the VALENCE SHELL are called VALENCE ELECTRONS
How many VALENCE ELECTRONS in GROUP 1?
How many VALENCE ELECTRONS in GROUP 2?
How many VALENCE ELECTRONS in GROUP 16?
How many VALENCE ELECTRONS in GROUP 18?
What Do You Notice about the Number of Valence Electrons for
Elements in the Same Group?
Most elements in the same group have the same
number of valence electrons
What Do You Notice About the Placement and the Number of Valence
Electrons for Elements in the Same Period?
Elements in the same period have valence electrons in the same
shell AND the number of valence electrons is increasing going
left to right within the group by one
What Do You Notice About the period number and the number of occupied
shells for Elements in the Same Period?
The period number indicates the number of shells
that have electrons.
All ATOMS want to be
like
NOBLE GASES!
If there are 8 electrons in a shell = STABLE OCTET
ATOMS WANT TO HAVE A STABLE OCTET!!!!!! ALL THE TIME!!
Unreactive because their atoms have filled valence shells =
they are stable = NOBLE GAS STABILITY
NOBLE GASES!
UNREACTIVE = they do not lose or gain electrons
Each atom wants to have as many of valence electrons as the nearest noble gas.
Metals want to
LOSE ELECTRONS
How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST
NOBLE GAS
An atom of any metal can lose electrons and form
positive ions
Each atom element to have as many of
valence electrons as the nearest noble gas.
Non - Metals
want to GAIN
ELECTRONS
How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST
NOBLE GAS
An atom of any non-metal except a noble gas can
gain electrons and form negative ions
How many electrons
does sodium, Na,
want to have?
10 electrons
Each atom element to have as many of
valence electrons as the nearest noble gas.
How many electrons
does oxygen, O, want
to have?
10 electrons
Each atom element to have as many of
valence electrons as the nearest noble gas.
How Do Atoms Become Ions? Atoms WILL gain or lose electrons because they want to be as stable as the NEAEREST
NOBLE GAS
Ions have the same electron arrangement as the
nearest noble gas
What Element is this?
18 p
22 n
argon
Bohr Diagrams Worksheet
1. How many protons does this element have?
2. How many electrons does this element have?
3. How many valence shells does this element have?
4. How many valence electrons does this element have?
5. How many occupied shells does this element have?
6. What is the identity of this element?
BOHR DIAGRAMS Practice (worksheet)
Draw Bohr Diagrams for:
hydrogen
Sodium ion
Phosphorus ion
Neon ion
calcium ion
First shell: 2 electrons
Second shell: 8 electrons
Fourth shell: 8 electrons
Third shell: 8 electrons
MOLECULES and IONIC COMPOUNDS
Atoms combine with different atoms to form compounds (thanks to electrons)
Forces that hold atoms together are called CHEMICAL BONDS
SHARING ELECTRONS DONATING ELECTRONS
Covalent Bonds Ionic Bonds
Atoms combine with different atoms to form compounds (thanks to electrons)
Forces that hold atoms together are called CHEMICAL BONDS
MOLECULES IONIC COMPOUNDS
Covalent Bonds Ionic Bonds
MOLECULES and IONIC COMPOUNDS
These bonds arise when
VALENCE ELECTRONS interact
Each atom attempts to have
as many of valence electrons
as the nearest noble gas.
MOLECULES and IONIC COMPOUNDS
Forces that hold atoms together are called CHEMICAL BONDS
IONS Atom or a group of atoms with net negative or
positive charge
POSITIVELY CHARGED ION =
NEGATIVELY CHARGED ION =
CATION ANION
IONIC COMPOUNDS Formed by an attraction of positively charged ion and
negatively charged ion
Chemical formula
IONIC COMPOUNDS Formed when electrons are transferred from a metal to
a non - metal
Chemical formula
IONS Cations and Anions are attracted to each other
IONIC BONDING
Draw the Bohr model diagram for NaCl
Draw the Bohr model diagram for NaCl
Draw the Bohr model diagram for NaCl
Draw the Bohr model diagram for KF
Draw the Bohr model diagram for CaF
MOLECULES and IONIC COMPOUNDS Atoms combine with different atoms to form compounds
(thanks to electrons)
Forces that hold atoms together are called CHEMICAL BONDS
SHARING ELECTRONS DONATING ELECTRONS
Covalent Bonds Ionic Bonds
Covalent Bonds Valence Electrons are shared between atoms
Covalent Bonds • Unpaired electronsfrom each atom will pair together, forming a covalent bond.
• These two electrons are sometimes called a bonding pair.
hydrogen fluorine
+
electrons are
shared
Hydrogen
fluoride
BONDING pair of
electrons
Covalent Bonds • An unpaired electron from each atom will pair together, forming a covalent bond.
• These two electrons are sometimes called a bonding pair.
F2 CF4 H2