Section 1.2 Q-cards Flashcards
Study for the unit test. its not a unit test tho its just 1.2 1.3 2.1
By the mid-1800s, how many elements were known to exist?
By the mid-1800s, about 63 elements were known to exist.
History of the Periodic Table.
Demitri Mendeleev - a Russian chemist and teacher arranged elements in increasing order of atomic mass.
Mendeleev left blank for yet-undiscovered elements. He had made good predictions
In 1869, he created the first “periodic table” framework.
In 1913 Henry Moseley - a British physicist, arranged elements according to increasing atomic number - the arrangement we use today.
Periodic Law, what is it?
It states that elements arranged in order of increasing atomic number show a periodic table with groups or families.
Group?
A column in the periodic table. The elements in each group have similar traits, bonding properties, and electron arrangement. elements can be categorized as:
Alkali metals
Alkaline Earth metals
Halogens
Noble Gases
Number of valence electrons is completely predictable from the group number, except for the elements in group 12.
Period?
It is a row in the periodic table.
What are the properties of metals?
Solid at room temperature with the exception of mercury
Tend to be shiny
Good conductors of electricity
Malleable and ductile
What are the properties of non-metals?
Solid at room temperature
Some are gases
Only Bromine is liquid among non-metals
Not shiny, Doesn’t conduct electricity
Non-malleable or ductile
What are the properties of Metalloids?
Their properties is between metal and non-metal
Brittle and often poor conductors of electricity
Elements according to black categorization
Main groups?
Groups 1,2, and 12 through 18 are the main-group elements they are the most prevalent elements on earth.
Transition Elements?
The center of the table contains the transition element - sometimes called the transition metals.
Can have up to 18 electrons in their outer shell.
Their electron configurations are more complex than those of the main-group elements in the periodic table.
Inner Transition Elements?
Inner transition elements lie at the bottom of the table.
Period 6 reads “La-Lu” meaning that all of the elements from lanthanum through lutetium belong there. Period 7 reads “Ac-Lr” indicating the location of the elements from actinium through lawrencium.
They can have as many as 32 electrons in some of their valence shells.
Reactivity of Elements?
The degree to which an element reacts with another depends on the electron arrangement of the atom.
The general trends are
Main group metals: reactivity increases down the group
Non-metals: reactivity increases up the group.
Reactivity is greater to the far left and right of the periodic table.
Is there any execution to this pattern of reactivity?
Yes. Noble Gases - they don’t react because they have a full outer shell of electrons and therefore cannot participate in bonding/reacting.
Which Atoms would be considered the MOST reactive?
Those with 1 or 7 valence electrons because they are closest to being stable with a full outer shell.
Which metal is the most reactive?
Francium is the most reactive.
