4.4 Structures of the Periodic Table Flashcards
What is an element?
A pure substance that cannot be broken down into simpler substances
How many elements are natural here on Earth?
90
How many elements are synthesized by scientists?
25
What does periodic mean?
To occur at regular/predictive intervals
What is the Periodic Table of Elements?
Regular variations of properties arranged by increasing atomic number and shows patterns in properties
Who is Dmitri Mendeleev and what was significant about him?
Scientist that grouped elements according to atomic masses and properties - basis of periodic table
Why were there gaps in his periodic table?
They were spaces for missing elements
What did Henry Moseley do to the periodic table?
Used atomic number to arrange the periodic table
How many classes of elements are there and name them?
3, which is metal, nonmetal, and metalloids
How are elements grouped on the periodic table?
Grouped by similar chemical, physical properties and electron arrangement
Where are the metals located on the periodic table?
Left of the zig zag except hydrogen
What are the chemical properties of metals?
- Few electrons in valence shell
- Loses electrons easily
- Positive charge -> makes cations
What are the physical properties of metals?
- Ductile and malleable
- Good conductors
- Shiny
- Solid at room temperature
Where are the nonmetals located on the periodic table?
Right of zig zag
What are the chemical properties of nonmetals?
- Almost/full valence shells
- Tends to gain electrons
- Negative charge
- Makes anions
What are the physical properties of nonmetals?
- Not ductile or malleable
- Bad conductors
- Mostly solid
- Some are gases at room temp
Where are the metalloids located on the periodic table?
In the zig zag
What are the chemical properties of metalloids?
- Half full valence shells (mostly)
- Makes cations/anions depending on environment
What are the physical properties of metalloids?
- Have properties of metals and nonmetals
- No way to know which properties of each
What is the correlation between periods on the periodic table and number of energy levels?
Same period = same number of energy levels
Atoms in the same group have the same number of electrons, except ___________
d block and f block
Why are elements within a family share similar chemical and physical properties?
They have the same number of valence electrons
How many groups are there on the periodic table?
18
What group is alkali metals in?
Group 1 elements
