Study 18th of September 2019 Flashcards
• Elements are listed in order of what in the periodic table?
• Elements are listed in order of increasing atomic number
Elements are arranged according to what in the periodic table
arranged according to the number of electrons in the outer shells of their atoms
What elements are placed in columns called ______
Elements whose atoms have the same number of outer electrons are placed in columns called groups and have similar chemical properties
The elements in the horizontal row have what name
Period
The elements in the horizontal row have the same number of what
• The elements in a horizontal row, or period, have the same number of electron shells.
What is the period number of an element
The period number of an element is the number of electron shells in an atom of that element
What are vertical columns in the periodic table called
Groups
What happens to the size of the atoms as we move from ____ to ____ across a period
decrease
What is periodic law
All the elements in a group have the same electron configuration in their outermost shells, i.e. the same number of electrons in their outermost shell
Why do Sizes of the atoms decrease as we move from left to right across a period
This is due to the increasing number of protons in the nucleus, so the electrical attraction between the nucleus and the orbiting electrons gets stronger and pulls the electrons closer to the nucleus
What are valence electrons
• The electrons in the outer most electron shell are called valence electrons
What is a valence shell
• The shell containing electrons that is furthest from the nucleus is called the valence shell
Define valency
In chemistry, valency is the power of an atom of an element to combine with other atoms, measured by the number of electrons which an atom will give, take, or share to form a chemical compound
What is valency related to
This is related to the number of spaces left in an atom’s electron shells, which is why the only elements with valencies of zero are the noble gases
Typical definition of valency
Valence is, typically, the number of electrons needed to fill the outermost shell of an atom
What is valence
Valence is the number of electrons with which a given atom generally bonds or number of bonds an atom forms
What is the first group in the periodic table called
• The first group is called the alkali metals (shiny, soft, highly reactive metals)
What is the second group of the periodic table called
• The second group is the alkaline-earth metals (shiny, soft, somewhat reactive metals)
What are groups 3-12 called in the periodic table
Groups 3-12 are called the transition metals (the d-block)
What are groups 13-15 called in the periodic table
Groups 13-15 are not named
What is group 16 called in the periodic table
• Group 16 are the chalcogens (some critical to life, some toxic)
What are group 17 or 7 called in the periodic table
• Group 17 or 7 are the halogens (salt producing)
What are group 18 or 8 called in the periodic table
Group 18 or 8 are the noble gases or inert gases and are basically inert
Group 18 with noble gases are what
• Group 18 with Noble Gases are stable ̶ have 8 valence e- (except He which has 2 valence e-
What is the reactivity of noble gases
• Noble gases are usually unreactive; this is because they have full valence shells
An element with a full valence shell is a what element?
• An element with a full valence shell is a “happy” element
For 2 atoms to join together atoms must
• For two atoms to join together atoms must gain, lose or
share electrons
Elements with full valence shells do not what
• Elements with full valence shells do not easily gain or lose electrons
