15 Questions
What is the general number of valence electrons for transition metals?
Two
Which of the following elements has three valence electrons?
Lawrencium
According to the octet rule, when are atoms or ions considered most stable?
When their valence shell contains eight electrons
Which of the following elements does NOT start with a full valence shell?
Oxygen
How many bonds does carbon typically form due to its valence electron configuration?
Four bonds
What are valence electrons responsible for?
Controlling the chemical reactivity of elements
Which type of electrons are the other electrons in an atom besides valence electrons?
Core electrons
How many valence electrons does sodium (Na) have?
One
In the electron configuration for carbon (C), how many core electrons are there?
Two
How can you count the number of valence electrons for Group A elements in the periodic table?
Count from the left edge of the periodic table, skipping non-Group A elements
How many valence electrons does a fluorine atom have?
7
In the Lewis structure of arsenic trifluoride, why is arsenic the central atom?
It needs the most bonds.
Why does nitrogen gas have a triple bond between the two nitrogen atoms?
To satisfy the octet rule.
In the Lewis structure of methane, why is carbon the central atom?
It needs the most bonds.
How many lone pairs are there on each nitrogen atom in nitrogen gas?
1
Study Notes
Valence Electrons and Electron Configuration
- Transition metals typically have a varying number of valence electrons.
- Boron (B) is an element that has three valence electrons.
Octet Rule and Stability
- Atoms or ions are considered most stable when they have a full outer energy level, or octet, according to the octet rule.
Elements and Valence Shells
- Hydrogen (H) is an element that does not start with a full valence shell.
Bond Formation and Valence Electrons
- Carbon (C) typically forms four bonds due to its valence electron configuration.
- Valence electrons are responsible for forming bonds between atoms.
Core Electrons and Electron Configuration
- Core electrons are the other electrons in an atom besides valence electrons.
- Sodium (Na) has one valence electron.
- In the electron configuration for carbon (C), there are two core electrons.
Counting Valence Electrons in the Periodic Table
- The number of valence electrons for Group A elements in the periodic table can be counted by looking at the group number.
Element Valence Electrons
- A fluorine (F) atom has seven valence electrons.
Lewis Structures
- In the Lewis structure of arsenic trifluoride, arsenic is the central atom because it is less electronegative than fluorine.
- In the Lewis structure of methane, carbon is the central atom because it is less electronegative than hydrogen.
- Nitrogen gas (N2) has a triple bond between the two nitrogen atoms because it allows each nitrogen atom to achieve a full octet.
- There are three lone pairs on each nitrogen atom in nitrogen gas.
Learn about valence electrons, which play a crucial role in determining the chemical reactivity of elements, and core electrons that are not involved in chemical bonding. Explore how to identify valence electrons in an atom's electron configuration.
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