The Periodic Table Atomic Number (number of protons) Symbol Atomic Mass Period.
Atomic Structure BASIC INFORMATION. atoms are made up of: protons (+ charge) neutrons (no charge)...
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Transcript of Atomic Structure BASIC INFORMATION. atoms are made up of: protons (+ charge) neutrons (no charge)...
• atoms are made up of: protons (+ charge)neutrons (no charge)electrons (- charge)
• atomic number = # protonsLithium’s atomic # is 3
• atomic mass = # protons + # neutronsLithium’s atomic mass is 6.94 (round to 7)
• in a neutral atom: # protons = # electrons
Lithium has 3 electrons• the # neutrons = atomic mass - # protons
Lithium has 4 neutrons (7 – 3 = 4)
About Atoms…..
ELECTRONS ARE ELECTRONS ARE ARRANGED IN ARRANGED IN
“SHELLS” AROUND “SHELLS” AROUND THE NUCLEUSTHE NUCLEUS
Element: Boron Mass =
Symbol: B # P =
# Neutrons = # e =
# Valence Electrons =
The first electron shell can hold up to 2
electrons
The second electron shell can hold up to 8
electrons
The third electron shell can hold up to 8
electrons
In biology, we usually don’t have to deal
with elements having more than three electron shells!
Which of an atom’s electrons are involved in bonding with
other atoms? Only the electrons in its Only the electrons in its outermostoutermost shell! shell!
These electrons are called the These electrons are called the valence valence electronselectrons!!
Hydrogen atoms Hydrogen atoms have have
1 valence electron1 valence electron
Helium atoms Helium atoms havehave
2 valence 2 valence electronselectrons
Element: Boron Mass # =
Symbol: B # P =
# Neutrons = # e =
# Valence Electrons =
First shell 2 electrons
Second shell 8 electrons
Third shell 8 electrons
Fourth shell 16 electrons
• atoms are made up of: protons (+ charge)neutrons (no charge)electrons (- charge)
• atomic number = # protonsLithium’s atomic # is _____
• atomic mass = # protons + # neutronsLithium’s atomic mass is _____
•in a neutral atom: # protons = # electrons
Lithium has _____ electrons• the # neutrons = atomic mass - # protons
Lithium has _____ neutrons
About Atoms…..
ELECTRONS ARE ELECTRONS ARE ARRANGED IN ARRANGED IN
“SHELLS” AROUND “SHELLS” AROUND THE NUCLEUSTHE NUCLEUS
Element: Boron Mass =
Symbol: B # P =
# Neutrons = # e =
# Valence Electrons =
The first electron shell can hold up to
_____ electrons
The second electron shell can hold up to
_____ electrons
The third electron shell can hold up to
_____ electrons
In biology, we usually don’t have to deal
with elements having more than three electron shells!
Which of an atom’s electrons are involved in bonding with
other atoms? Only the electrons in its Only the electrons in its ________________________ shell! shell!
These electrons are called the These electrons are called the ________________________________!!