a
Name an example of an alkaline-earth metal
What type of element is iron (Fe)?
Transition metal
Why is potassium located to the left of calcium on the periodic table?
What type of elements are on the right side of the periodic table?
Non-metals
Name an example of a halogen
Florine, chlorine, bromine, iodine, astatine, tennessine
What are ions?
atoms that gain or lose electrons
How many valence electrons do group 15 elements have?
5
The order of elements in the periodic table is based on...
the number of protons in the nucleus
Why are noble gases considered "inert" ?
They are unreactive because they already have full outer shells
Why did Mendeleev leave some gaps in his periodic table?
The elements that would fit there weren't discovered yet
The atoms of elements that are in the same group have the same number of...
Valence electrons
How many electrons does selenium want to gain/lose? AND what charge will this make it?
gain 2 electrons; -2
In Mendeleev's periodic table, elements in each column had similar...
Chemical properties/characteristics
Name an element that is a semiconductor
Boron, silicon, arsenic, germanium, antimony, tellerium, polonium, astatine
Different isotopes of the same element have different...
number of neutrons
Group 1 elements form ions with what charge?
+1
How was Mendeleev's periodic table arranged?
by increasing atomic mass
What is a compound?
Forms when two or more atoms join through chemical bonds
What is the process of ionization?
losing or gaining electrons
Which two groups on the periodic table are the most reactive AND WHY???
alkali metals and halogens, they are so reactive because they are each only one electron away from having a full outer shell
When did Mendeleev create a new row in his periodic table?
when chemical properties were repeated
What is the definition of a semiconductor?
A substance that can conduct heat and electricity under certain conditions
List 3 properties of metals
shiny, malleable, ductile, good conductors of heat/electricity
List 3 properties of non-metals
brittle, dull, poor conductors of heat/electricity
What is the formula to find the charge of an atom/ion?
charge= #protons - #electrons