Chapter 11 Introduction to Atoms

The History of Atomic Theory ___________________ proposed that all atoms are _________, __________ particles made up of a single material formed into different _____________ and ____________. He also said that that atoms are always _____________ and can form different _________________ by ______________ together. Democritus small hard shapes sizes moving materials joining In the 1700s, ________ ____________ came up with an atomic theory with 3 parts: 1. All substances are made of __________ which are small particles that cannot be ____________, _____________, or ___________________. 2. Atoms of the same ________________ are exactly alike and atoms of different _______________ are ______________. 3. Atoms __________ with other atoms to make new ___________________. John Dalton atoms created divided destroyed element element different join substances 3. In 1897, ______________________discovered that there are small particles _______________ the atom. He found that these particles had a _________________ charge. He called the particles ___________________, now known as _______________. He came up with a model of the atom known as the ___________________ model, where the atom is mostly ______________ charged material with ________________located throughout, so that the entire atom would be neutral in charge. J.J. Thomson inside negative corpuscles electrons plum-pudding positively electrons

Ernest Rutherford 4. In 1909, ________________________ aimed a beam of ____________ particles at some gold foil and found that most of the particles ____________ _______________ the foil, some were ______________ a little, and a few bounced straight back. He concluded that atoms have a small, dense, positively charged _______________ in the center with ______________ orbiting around it, and that atoms are mostly _____________ ______________. alpha went through deflected nucleus electrons empty space 5. In 1913, __________________ came up with a model of the atom where the _______________ travel in definite ______________ around the nucleus. These _______________ can jump from one _____________ to the next, but cannot stay _________________ the levels. Neils Bohr electrons paths level electrons between

The work of ____________________ and ____________________ contributed to the modern atomic theory, which says that the exact path of a moving electron cannot be _______________. There are _______________ where the electron is likely to be called _______________ ____________. Erwin Schrodinger Werner Heisenberg predicted regions electron clouds Atoms consist of 3 _______________ _______________: 1. Protons: ________________ charged particles in the ____________ of the atom. Their mass is equal to 1 AMU (__________ _______ _____). An AMU = __________________ g. 2. Neutrons: _________________ particles in the _____________ of the atom. Their mass is _________________. 3. Electrons: ________________ charged particles within the _________ _____________ of an atom (outside the ______________). Their mass is about _________ AMU and is usually considered to be ___________. subatomic particles positively nucleus atomic mass unit 1.7 x 10-24 uncharged nucleus 1 AMU negatively electron cloud nucleus 1/1800 zero The _____________ of an atom is ______________. Atoms can __________ 1 or more electrons and become _________________ charged _________ or _____________ 1 or more electrons and become ______________ charged __________. A neutral atom has equal numbers of ____________ and _________. charge zero lose positively ions gain negatively ions protons electrons

Elements: All atoms of a particular element have the same number of ___________ in their nuclei. The number of protons is the ___________ _____________ of the element or atom. Neutral atoms will have the same number of _______________. For example, all atoms of hydrogen have ___ proton in the nucleus. All atoms of helium have ____ protons in the nucleus. All atoms of carbon have ____ protons in the nucleus. protons atomic number electrons 1 2 6 Different atoms of the same element may have different masses. This is because they can have different numbers of ______________ in the nucleus. For example, an atom of hydrogen can have one ____________ and _______ neutrons in its nucleus, or one _____________ and ______ neutron, or one ____________ and _______ neutrons. These atoms of the same element with different masses are called ______________. neutrons proton zero proton one proton two isotopes

Isotopes: atoms that have the __________ number of ____________ but different numbers of _______________. Some isotopes of an element may be ______________ while others may be _________________. All isotopes of a particular element have the same _______________ and ______________ properties. same protons neutrons stable radioactive chemical physical Mass Number: This is equal to the sum of the ____________ plus the ______________ of an atom. The mass of the ____________ is not included because it is so _____________. The number for an element’s mass listed on the periodic table is a weighted ________________ of all the naturally occurring _______________ of a particular _________________. protons neutrons electrons small average isotopes element Example: An atom has 6 protons, 8 neutrons, and 6 electrons. What is the a. atomic number? ______ b. mass number? ______ c. element? _______________ Example: If an atom of sulfur has a mass number of 34, how many neutrons does the atom have? ______ 6 14 carbon 18

Calculating Atomic Mass: Multiply the mass number of each _______________ by its __________________ and add them all together. Example: The percentages for the isotopes of copper are 69% Cu-63 and 31% Cu-65. What is the atomic mass of Copper? ____________________________________________ isotope percentage .69 x 63 = 43.47 amu .31 x 65 = 20.15 amu 43.47 + 20.15 = 63.62 amu Example: The 5 isotopes of titanium are: Ti-46 (8.0%) ______________________ Ti-47 (7.3%) ______________________ Ti-48 (73.8%) ______________________ Ti-49 (5.5%) ______________________ Ti-50 (5.4%) ______________________ Total: ____________________ 46 x 0.08 = 3.68 amu 47 x .073 = 3.431 amu 48 x .738 = 35.424 amu 49 x .055 = 2.695 amu 50 x .054 = 2.7 amu 47.93 amu Forces acting in Atoms 1. Gravity – This depends on the _________ and ____________ between 2 objects. Since atoms are so _____________, this force is very ____________ in atoms. mass distance small weak

2. Electromagnetic Force – Objects with the same charge __________ each other while objects with opposite charges _____________ each other. ____________ and ______________ are attracted to each other because they have _______________ charges. The ________________________ force holds the electrons around the protons. repel attract Protons electrons opposite electromagnetic 3. Strong Force – At the close distances between __________ in the nucleus, the ____________ force holds them together and is stronger than the ______________________ force that would cause them to fly apart. protons strong electromagnetic 4. Weak Force – This force plays a role in ___________________ atoms where a ______________ can change into a _____________ and an _______________. radioactive neutron proton electron

Chapter 11 Introduction to Atoms

The History of Atomic Theory ___________________ proposed that all atoms are _________, __________ particles made up of a single material formed into different _____________ and ____________. He also said that that atoms are always _____________ and can form different _________________ by ______________ together. moving In the 1700s, ________ ____________ came up with an atomic theory with 3 parts: 1. All substances are made of __________ which are small particles that cannot be ____________, _____________, or ___________________. 2. Atoms of the same ________________ are exactly alike and atoms of different _______________ are ______________. 3. Atoms __________ with other atoms to make new ___________________. 3. In 1897, ______________________discovered that there are small particles _______________ the atom. He found that these particles had a _________________ charge. He called the particles ___________________, now known as _______________. He came up with a model of the atom known as the ___________________ model, where the atom is mostly ______________ charged material with ________________located throughout, so that the entire atom would be neutral in charge.

4. In 1909, ________________________ aimed a beam of ____________ particles at some gold foil and found that most of the particles ____________ _______________ the foil, some were ______________ a little, and a few bounced straight back. He concluded that atoms have a small, dense, positively charged _______________ in the center with ______________ orbiting around it, and that atoms are mostly _____________ ______________. 5. In 1913, __________________ came up with a model of the atom where the _______________ travel in definite ______________ around the nucleus. These _______________ can jump from one _____________ to the next, but cannot stay _________________ the levels.

The work of ____________________ and ____________________ contributed to the modern atomic theory, which says that the exact path of a moving electron cannot be _______________. There are _______________ where the electron is likely to be called _______________ ____________. Atoms consist of 3 _______________ _______________: 1. Protons: ________________ charged particles in the ____________ of the atom. Their mass is equal to 1 AMU (__________ _______ _____). An AMU = __________________ g. 2. Neutrons: _________________ particles in the _____________ of the atom. Their mass is _________________. 3. Electrons: ________________ charged particles within the _________ _____________ of an atom (outside the ______________). Their mass is about _________ AMU and is usually considered to be ___________. The _____________ of an atom is ______________. Atoms can __________ 1 or more electrons and become _________________ charged _________ or _____________ 1 or more electrons and become ______________ charged __________. A neutral atom has equal numbers of ____________ and _________.

Elements: All atoms of a particular element have the same number of ___________ in their nuclei. The number of protons is the ___________ _____________ of the element or atom. Neutral atoms will have the same number of _______________. For example, all atoms of hydrogen have ___ proton in the nucleus. All atoms of helium have ____ protons in the nucleus. All atoms of carbon have ____ protons in the nucleus. Different atoms of the same element may have different masses. This is because they can have different numbers of ______________ in the nucleus. For example, an atom of hydrogen can have one ____________ and _______ neutrons in its nucleus, or one _____________ and ______ neutron, or one ____________ and _______ neutrons. These atoms of the same element with different masses are called ______________.

Isotopes: atoms that have the __________ number of ____________ but different numbers of _______________. Some isotopes of an element may be ______________ while others may be _________________. All isotopes of a particular element have the same _______________ and ______________ properties. Mass Number: This is equal to the sum of the ____________ plus the ______________ of an atom. The mass of the ____________ is not included because it is so _____________. The number for an element’s mass listed on the periodic table is a weighted ________________ of all the naturally occurring _______________ of a particular _________________. Example: An atom has 6 protons, 8 neutrons, and 6 electrons. What is the a. atomic number? ______ b. mass number? ______ c. element? _______________ Example: If an atom of sulfur has a mass number of 34, how many neutrons does the atom have? ______

Calculating Atomic Mass: Multiply the mass number of each _______________ by its __________________ and add them all together. Example: The percentages for the isotopes of copper are 69% Cu-63 and 31% Cu-65. What is the atomic mass of Copper? ____________________________________________ Example: The 5 isotopes of titanium are: Ti-46 (8.0%) ______________________ Ti-47 (7.3%) ______________________ Ti-48 (73.8%) ______________________ Ti-49 (5.5%) ______________________ Ti-50 (5.4%) ______________________ Total: ____________________ Forces acting in Atoms 1. Gravity – This depends on the _________ and ____________ between 2 objects. Since atoms are so _____________, this force is very ____________ in atoms.

2. Electromagnetic Force – Objects with the same charge __________ each other while objects with opposite charges _____________ each other. ____________ and ______________ are attracted to each other because they have _______________ charges. The ________________________ force holds the electrons around the protons. 3. Strong Force – At the close distances between __________ in the nucleus, the ____________ force holds them together and is stronger than the ______________________ force that would cause them to fly apart. 4. Weak Force – This force plays a role in ___________________ atoms where a ______________ can change into a _____________ and an _______________.