What’s the Matter? Atomic Basics
OBJECTIVES Describe the charge, location, and relative masses of protons, neutrons, and electrons Calculate the number of particles in an atom using the atomic number, mass number, and overall charge. Identify isotopes and explain their similarities/differences.
What’s the matter? EVERYTHING! Matter = anything that has mass and takes up space
What’s the matter? EVERYTHING! Matter = anything that has mass and takes up space Matter is made up of tiny particles called atoms
What’s inside an atom?
Inside the atom 3 basic particles make up an atom: protons, neutrons, & electrons.
Inside the atom 3 basic particles make up an atom: protons, neutrons, & electrons. Protons and neutrons make up the nucleus of an atom.
Inside the atom 3 basic particles make up an atom: protons, neutrons, & electrons. Protons and neutrons make up the nucleus of an atom. Protons = particles that have a positive charge
Inside the atom 3 basic particles make up an atom: protons, neutrons, & electrons. Protons and neutrons make up the nucleus of an atom. Protons = particles that have a positive charge Neutrons = particles that have no electric charge
Inside the atom 3 basic particles make up an atom: protons, neutrons, & electrons. Protons and neutrons make up the nucleus of an atom. Protons = particles that have a positive charge Neutrons = particles that have no electric charge Electrons = negatively charged particles that move around the nucleus
More about atoms… Atoms are neutral because they have an equal number of positive and negative charges. If an atom loses or gains an electron, the atom becomes an ion (atom with a charge).
What makes one atom different from another?
Identifying Elements Atomic number = # of protons in an atom's nucleus
Identifying Elements Atomic number = # of protons in an atom's nucleus The number of protons determines what element something is This number also equals the number of electrons in the atom's electron cloud
Identifying Elements Atomic number = # of protons in an atom's nucleus The number of protons determines what element something is This number also equals the number of electrons in the atom's electron cloud Mass number= # protons + # neutrons
Identifying Elements Atomic number = # of protons in an atom's nucleus The number of protons determines what element something is This number also equals the number of electrons in the atom's electron cloud Mass number = # protons + # neutrons
Are all atoms of an element the same?
Isotopes Isotopes = atoms of the same element that have different numbers of neutrons
Isotopes Isotopes = atoms of the same element that have different numbers of neutrons some isotopes are unstable (radioactive)
Isotopes Isotopes = atoms of the same element that have different numbers of neutrons some isotopes are unstable (radioactive) You can identify each isotope of an element by its mass number – each isotope has a different mass number.
Calculating the Mass of an Element Atomic mass = average mass of all the isotopes of an element
What else is there to know about protons, neutrons, and electrons?
More about protons, neutrons, and electrons
More about protons, neutrons, and electrons Decide what the atom will be (which element). Determine the number of electrons.
More about protons, neutrons, and electrons Decide what the atom will be (which element). Determine the number of electrons. Neutrons: Are needed to keep the protons together. (since protons repel each other) Were the last of the three to be discovered
More about protons, neutrons, and electrons Decide what the atom will be (which element). Determine the number of electrons. Neutrons: Are needed to keep the protons together. (since protons repel each other) Were the last of the three to be discovered Electrons: Decide how the atom will get along with other atoms (chemical properties). Have the smallest mass of all three; close to zero
Where exactly do electrons “hang out” outside the nucleus?
Energy levels in atoms Electron shells are the orbits followed by electrons around the nucleus.
Energy levels in atoms Electron shells are the orbits followed by electrons around the nucleus. Each electron shell can hold only a certain number of electrons. 1st shell fits 2 total electrons 2nd shell fits 8 total electrons 3rd shell fits 8 total electrons 4th shell fits 2 total electrons USE THIS SLIDE IN FUTURE
ATOMIC MATH Don’t worry – it’s just ADDING and SUBTRACTING!
For each element in the periodic table, you can find the following information: Atomic Number Symbol Name Atomic Mass protons electrons Atomic number equals the number of __________ or ___________. Atomic mass equals the number of ___________ + ____________. protons neutrons
DO WITH WHITEBOARDS
Use the information provided to answer the questions. 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine?
The answers are … What is the atomic number for Chlorine? 17 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? 17
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron?
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? 10.81 or 11
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na?
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? 11
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He?
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He? 2
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He? How many electrons are in an atom of Cl?
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He? How many electrons are in an atom of Cl? 17
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He? How many electrons are in an atom of Cl? How many neutrons are in an atom of Sodium?
The answers are … What is the atomic number for Chlorine? 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 What is the atomic number for Chlorine? What is the atomic mass for Boron? How many protons are in an atom of Na? How many neutrons are in an atom of He? How many electrons are in an atom of Cl? How many neutrons are in an atom of Sodium? 12
How many total particles would be in the nucleus of Chlorine? The answers are … 5 B Boron 10.81 2 He Helium 4.003 11 Na Sodium 22.990 17 Cl Chlorine 35.453 Bonus Questions: How many total particles would be in the nucleus of Chlorine? What are the two possible mass numbers for an atom of Boron? Which one is more common?