Valence electrons are the outermost shell electrons of an atom that are involved in bonding. Elements in the same group on the periodic table have the same number of valence electrons because they exhibit similar chemical properties based on their valence electron configuration. Atoms seek to attain a full outer shell of 8 electrons to achieve stability through gaining, losing or sharing valence electrons in chemical bonds.
Chemical bonds- Properties of Ionic and Covalent compoundsSyed Amirul Aiman
This slide was used in the microteaching practice conducted by Dr. Denis Andrew D. Lajium for Teaching Method I (Chemistry) - TK30103.
all right reserve.
It is a powerpoint presentation that discusses about the lesson or topic: Percentage Composition. It also talks about the definition, concepts and examples about the Percentage Composition.
Chemical bonds- Properties of Ionic and Covalent compoundsSyed Amirul Aiman
This slide was used in the microteaching practice conducted by Dr. Denis Andrew D. Lajium for Teaching Method I (Chemistry) - TK30103.
all right reserve.
It is a powerpoint presentation that discusses about the lesson or topic: Percentage Composition. It also talks about the definition, concepts and examples about the Percentage Composition.
Lesson 8Chemical Bonding & NomenclatureYou should view all.docxsmile790243
Lesson 8
Chemical Bonding & Nomenclature
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*Read: Watch the Lecture as a slideshow, hit the space bar to move forward or just left click.
1
Topics:
Chemical Bonds
Lewis Dot Structures
Molecular Geometry
Polar Bonds
Naming Compounds
Writing Chemical Formulas
Naming Molecular Compounds
Lesson 8: Chemical Bonding and Nomenclature
2
2
Chemical Bonds
Sodium (Na) is a silver-colored metal that reacts so
violently with water that flames are produced when sodium
gets wet.
Chlorine (Cl) is a greenish-colored gas that is so poisonous that it was used as a weapon in World War I.
When the electrons of sodium metal and chlorine gas interact, the compound sodium chloride (NaCl) is formed, which is table salt.
Since the body is over 90% water, ingesting sodium metal would literally set someone on fire!
If we make a compound out of Na, we can make something totally different such as the table salt used to season our food.
3
Chemical Bonds
Atoms can interact with each other to form new substances called
compounds.
Compounds are formed when electrons in an atom’s last energy level interact and form chemical bonds. A chemical bond is an attractive force between atoms that holds them together.
An atom’s outermost energy level of electrons is called the valence shell (or valence level) and the electrons in the valence shell are called valence electrons.
4
Na Atom
Cl Atom
Sodium has 1 valence electron in the valence shell.
Chlorine has 7 valence electron in the valence shell.
Chemical Bonds
In ionic bonds, metals always lose electrons to nonmetals and become positive (or cations).
In ionic bonds, nonmetals always attract electrons from metals and become negative (anions).
Ionic compounds are neutral compounds made up of cations and anions.
Covalent bonds are formed between nonmetals and electrons are shared so no ions are formed.
Cl
nonmetal
Na
metal
O
nonmetal
O
nonmetal
Metal + Nonmetal = Ionic Compound
Nonmetal + Nonmetal = Covalent Compound
Chemical Bonds: Ionic
The octet rule states that atoms will gain, lose, or share
valence electrons in a way that will give each atom eight electrons in their valence shell.
Na has 1 electron in its valence shell and Cl has 7 electrons in its valence shell. Cl needs 1 valence electron to have 8 in its outer shell.
If Na transfers its 1 valence electron to Cl, Na’s second energy level becomes the valence shell, which already has 8 electrons.
Now, Na has a positive 1 charge and Cl has a negative 1 charge. But, the charge on NaCl is zero (the charges cancel each other out).
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Na Atom
Cl Atom
Ionic Bond
Chemical Bonds: Ionic
An Ionic bond is formed when there is a transfer of electrons from a metal to a nonmetal. Compounds formed by ionic bonds are ...
The Aufbau Principle requires that the electrons occupy the lowest possible energy level before filling up the next.
Pauli’s Exclusion Principle posits that no two electrons can have the same set of four quantum number; the spin quantum number limits the number of electrons in an orbital to a maximum of two.
Hund’s Rule requires that the electrons fill the orbitals in a subshell one by one, before pairing the electrons in an orbital spin in opposite directions.
A brief power point presentation designed to help introduce high school chemistry students to reading the periodic table and extracting information such as the number of valence electrons an element has, etc.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
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The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Ethnobotany and Ethnopharmacology:
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Impact of Ethnobotany in traditional medicine,
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The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
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Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
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2. What is a Valence Electron?
Valence electrons are the electrons in the outer shell
that bond with other atoms
3. What is a Valence Electron?
Valence electrons are the electrons in the outer shell
that bond with other atoms
= valence electron
4. What is a Valence Electron?
Valence electrons are the electrons in the outer shell
that bond with other atoms
= valence electron
5. What is a Valence Electron?
Valence electrons are the electrons in the outer shell
that bond with other atoms
Core electrons are under valence electrons
= valence electron
6. Outer Shells of Electrons
The number of valence electrons determines an
element’s chemical properties
For example, the noble gases on the right side of the
periodic table are inert
Inert = do not react with other atoms
7. Noble Gases
Noble gases are inert
because they have 8
outer shell (=valence)
electrons
Having 8 outer shell
electrons means the
outer shell is full, and
therefore can’t react
8. Periodic Table Groups
Columns on the periodic
table are called GROUPS
Elements in the same
group have similar
chemical properties.
This is because each group has the
same number of valence electrons
9. Valence Electrons in Groups
Elements in the periodic table are arranged in groups.
Each group has the same number of valence electrons….
Group 5A
Group 1A
Group 2A
Group 4A
Group 3A
Group 7A
Group 6A
Group 8A
Group 1A has 1
valence
electron, group
2A has 2
valence
electrons,
group 3A has 3
valence
electrons……….
10. Importance of Valence Electrons
The entire periodic table is arranged according to the
number of valence electrons each element has!!
The reason they arrange the periodic table this way is
because elements in each group react similarly (=same)
11. Octet Rule
The octet rule states that atoms like to have 8 valence
electrons.
Atoms that have 8 outer shell electrons are stable and
non reactive.
The noble gases
(group 8A) are
stable because
they all have 8
valence electrons
12. Lewis Structures
Lewis structures show ONLY valence electrons.
Examples:
Sodium (Na) is in group 1A,
so we know it has 1 valence
electron. Group 1A is
known as the alkali metals
Beryllium (Be) is in group
2A, so we know it has 2
valence electrons. Group
2A is known as the alkaline
earth metals
14. How to Draw Lewis Structures
1) Look at the element you want to draw the structure for
and see what group it is in.
2) Draw dots around the symbol according to how many
valence electrons it has.
Example: Draw a Lewis Structure for calcium
1) We see calcium (Ca) is
in group 2A, so it has 2
valence electrons
2)
Ca
15. Filling Electron Orbitals
Electrons fly around atoms in
their electron orbitals
There are S, P, D and F orbitals
We will only study 1S, 2S, 2P,
3S and 3P orbitals.
Orbitals fill in this order
1S is first
2S is second, then 2P……
16. Filling Electron Orbitals
Electron orbitals will fill in this order:
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
“1” means first energy level
Valence electrons are ONLY in the highest energy level!!
17. Filling Electron Orbitals
Electron orbitals will fill in this order:
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
“1” means first energy level
Valence electrons are ONLY in the highest energy level!!
“S” is the type, or shape of the orbital
1S orbital is round
18. Filling Electron Orbitals
Electron orbitals will fill in this order:
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
“2” is the second energy level
Valence electrons are ONLY in the highest energy level!!
19. Filling Electron Orbitals
Electron orbitals will fill in this order:
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
“2” is the second energy level
Valence electrons are ONLY in the highest energy level!!
“S” and “P” are the type, or shape of the orbitals
2S orbitals are round
2P orbitals
20. How to Fill Electron Orbitals
Example: give me the electron orbital configuration of sodium (Na)
1) We look at the periodic
table and see that sodium
has 11 electrons
2) Electrons are filled in the
following order
The 1S 2S and 2P electrons are CORE electrons; they don’t react
The 3S (highest energy level) will react; Na has ONE valence electron
21. Remember What We are Doing!!
Hydrogen (H) atom
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of Hydrogen?
“n” is the energy level, and
corresponds to our electron
diagram
n=1
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
H: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
22. Remember What We are Doing!!
Hydrogen (H) atom
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of hydrogen?
“n” is the energy level, and
corresponds to our electron
diagram
n=1
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
H: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
23. Remember What We are Doing!!
Hydrogen (H) atom
n=1
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of carbon?
“n” is the energy level, and
corresponds to our electron
diagram
n=2
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
C: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
24. Remember What We are Doing!!
Hydrogen (H) atom
n=1
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of carbon?
“n” is the energy level, and
corresponds to our electron
diagram
n=2
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
C: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
25. Remember What We are Doing!!
Hydrogen (H) atom
n=1
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of carbon?
“n” is the energy level, and
corresponds to our electron
diagram
n=2
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
C: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
26. Remember What We are Doing!!
Hydrogen (H) atom
n=1
We are showing what orbitals
electrons are in, and how many are
in them. What is the electron
orbital configuration of carbon?
“n” is the energy level, and
corresponds to our electron
diagram
n=2
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
C: 1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
27. How to Fill Electron Orbitals
Example: give me the electron orbital configuration of neon (Ne)
1) We look at the periodic table and see that neon
(Ne) has 10 electrons (electrons = to # of protons)
2) Electrons are filled in the following order
Lower level core electrons (level 1 here) DON’T react!
Level 2 (highest energy level) will react; Ne has 8 valence electrons!
28. Examples
Remember, only the highest
level (number) are valence
electrons:
-Li only has 1 valence
electron (2nd level)
-Mg only has 2 valence
electrons (3rd level)
You can see why atoms like
Ne are “happy” (=stable)
with 8 electrons now; their
valence shell is full and they
don’t want to give or lose
electrons.
29. Questions 20 Points!!
1. What is a valence electron? Draw an atom and show the valence electrons.
2. How many valence electrons do the following elements have:
Si, C, O, Ar, K
3. What does inert mean?
4. How many valence electrons do atoms like to have?
5. What do “groups” on the periodic table have in common?
6. Draw the Lewis structure for the following elements:
Ne, P, Mg, Na, Pb, Sb
7. Fill out the electron orbitals for the following elements
He, Ne, Na, Cl, B, Ar
Use the below diagram to guide you:
1S___ 2S___ 2P___ ___ ___ 3S___ 3P___ ___ ___
Bonus question: what element has the following electron configuration?
1s22s22p63s23p64s23d104p65s1