Name: Atoms & The Periodic Table WHAT IS AN ATOM? What is an atom? All are made of atoms. The, your and even are made of atoms. Atoms are. One atom is only one of a meter wide! DEMOCRITIS The idea of an atom was first developed around by Greek philosopher. Democritus believed that you could not break an object in half. At some point, you get to the bit of matter, which cannot be broken. He called this bit of matter an. JOHN DALTON In, English chemist John proposed and published his theory on atoms. Dalton believed was made of extremely small. Atoms of the same substance have identical, and other properties. Dalton also believed atoms could not be, or but could combine to form different chemical substances. J.J. THOMSON In, English physicist J.J. discovered the. Thomson discovered that an electron is a tiny, charged particle. From this finding, Thomson proposed the first of an atom. Thomson came up with his model of the atom in. According to Thomson, an atom was made of charged particles ( ) embedded in a soup of charges. Why was Thomson s atomic model called the plum pudding model? Draw a picture of Thomson s plum pudding model. ERNEST RUTHERFORD Ernest proposed an alternative model in. According to Rutherford, an atom is made of a central, charged region. He called this region the. Rutherford believed electrons surrounding the nucleus as a. He also believed the nucleus of the atom was and compared to the overall size of the atom.
Draw a picture of Rutherford s atomic model. Rutherford proved his model of the atom with a famous experiment known as the experiment. Who did Rutherford work with on this experiment? 1. 2. In this experiment, Rutherford shot a beam of charged particles, called particles, at a thin piece of foil. He recorded where the alpha particles as they struck the gold foil. What should have happened if Thomson s model was correct? What did Rutherford actually observe during this experiment? Rutherford believed his model explained these results: 1. Most particles through because an atom is mostly. 2. Some particles because they were deflected by negatively charged. 3. Some particles back because they bounced off the positively charged. NEILS BOHR In 1914, Neils modified Rutherford s model of the atom. Like Rutherford, Bohr believed an atom is made of a small, charged nucleus surrounded by charged electrons. How was Bohr s atomic model different from Rutherford s? Draw a picture of the Rutherford-Bohr atomic model.
ATOMIC STRUCTURE According to this model, there are 2 major regions of an atom: 1. 2. Atoms are VERY tiny! There are so small, that we use special units of to describe the and of atoms and particles within atoms. We measure the mass of atoms and the particles with an atom in units (u). One atomic mass unit equals kilograms. We measure the size of atoms in (pm). One picometer equals one of a meter. In other words, 1 picometer equals meters. An atom is approximately pm wide. particles are the particles found within an atom. They are: 1. 2. 3. Describe each subatomic particle in the table below. Particle Location Charge Mass Proton Neutron Electron Label the subatomic particles in the atom below. Because the nucleus contains and particles, the net charge of the nucleus is. A force known as the force holds the proton(s) and neutron(s) together in the. The space around the nucleus is charged because it contains negatively charged. stay in orbit around the nucleus due to force. This force an atom together. Although we cannot view the arrangement of particles within an atom, we have an instrument that allows us to see the of atoms. A microscope (STM) can view the atoms on the surface of an object.
ELEMENTS All atoms have the same of subatomic particles. A change in the of subatomic particles will change the of atom. An is a type of atom with the same number of. We also use the term element to describe a that is made of the same type of atom. An element is often abbreviated with a one of two letter. Complete the tables below to show the symbol for several common and important elements. Element Symbol Element Symbol Hydrogen Oxygen Nitrogen C Na Li Neon Helium Aluminum F Cl Fe ELECTRON SHELLS Electrons constantly move around the of an atom. They orbit the nucleus in specific or that surround the nucleus. A shell is also called an. It called so because a shell is associated with a certain amount of. The shell closest to the nucleus has the energy. in this shell have the least amount of energy. As you move away from the nucleus, the associated with a shell. Electrons in the shell furthest away from the nucleus have the energy. Each shell can only hold so many : - The first shell can hold electrons. - The second shell can hold electrons. - The third shell can hold electrons. - The fourth shell can hold electrons. In large atoms, you can find up to shells. No shell can hold more than electrons. ELECTRON CONFIGURATION How electrons are arranged in the shells of an atom is called. Electrons fill or take up in each shell. In general, electrons fill shells first because lower shells have energy. Once a shell is full, electrons begin to fill the next shell. BOHR DIAGRAM To show electron configuration, we draw a diagram called a Diagram. To draw a Bohr Diagram: 1. Draw a to represent the nucleus of an atom.
2. Write the of the element, the number of and number of inside the circle. 3. Draw around the circle to represent electron shells. 4. Draw electrons as on the rings. Remember, each ring can only hold so many electrons. Draw a Bohr diagram of Carbon, which has 6 protons, 6 neutrons and 6 electrons. Draw a Bohr diagram of Sodium, which has 11 protons, 12 neutrons and 11 electrons. VALENCE ELECTRONS The electrons found in the outermost orbital are called electrons. For this reason, the outermost shell is also called the shell. The number of electrons determines many chemical of an element. An atom cannot have more than valance electrons. An atom with valance electrons is said to have a outer shell. For example, has 8 valance electrons. Helium has a full valance shell with only electrons. Helium only has one shell. The maximum amount of electrons held in the first shell is electrons. Since the shell holds the maximum amount of it can hold, Helium is said to have a valance shell. ATOMIC NUMBER & MASS There are two important numbers associated with an element that help you determine the number of protons, neutrons and electrons in a neutral atom of that element: 1. 2.
ATOMIC NUMBER What is atomic number? Atoms of the same have the same number of and thus, the same number. ATOMIC MASS Atomic mass is the of an atom. Atomic mass is measured in. Atomic mass equals the sum of and in an atom. Remember, the mass of a proton is and the mass of a neutron is. Why do electrons not contribute to the mass of an atom? Example: Carbon has 6 protons and 6 neutrons. What is carbon s atomic mass? If you know an atom s number and the number of, you can calculate atomic mass. Write the equation to calculate atomic mass: + = If you know an atom s atomic mass and atomic number, you can calculate the number of in an atom. Write the equation to calculate number of neutrons: = Example: Nitrogen has an atomic mass of 14. Its atomic number is 7. How many neutrons are found in this atom? ATOMIC VARIATIONS The number of is the same for all atoms of a specific. A change in the number of will change the of atom the to which the atom belongs. The number of neutrons and electrons in an atom can without changing the to which the atom belongs. A change in the number of will change the of an atom. Different forms of atoms are called. The change in the number of will change the of an atom. Atoms with electric charge are called.
ISOTOPE An is a variety of an element with a different number of neutrons. The name of an isotope is the name of the element followed by a dash ( ) and the atomic of the isotope. Carbon has 6 protons. How would you write the name of: 1. Carbon with 6 neutrons? 2. Carbon with 7 neutrons? 3. Carbon with 8 neutrons? AVERGE ATOMIC MASS What is average atomic mass? To find average atomic mass: 1. Identify the different of the element and the atomic of each isotope. 2. Multiply the atomic mass of each by its (in decimal form). Percent is the percent the element is found in the. 3. Find the of these values. The sum is equal to atomic mass. Example: Chlorine Average atomic mass gives you an idea as to what the most common of an element is. To find the most common, round atomic mass to the nearest whole number. This trick works for most elements. RADIOACTIVE ISOTOPE Most isotopes are. Stable isotopes have a happy of protons and neutrons. Some isotopes are not. An unstable isotope is called a isotope. A radioactive isotope is called so because it emits. What is radiation? Why is radiation dangerous? RADIOACTIVE DECAY A radioactive isotope releases in order to become. This process is called. During decay, the atom emits. can be high-energy and/or particles.
As the atom undergoes radioactive decay, it becomes. As a stable isotope, the atom no longer emits. ION An element can gain or lose to form an. An ion is an atom with an charge. Neutral atoms have the same amount of and. These atoms have zero net charge. An ion does not have the amount of protons and electrons. These atoms have a or charge. When an atom loses an electron, it loses a charge. Therefore, the atom has more protons and is. A positive ion is called a. Complete the diagram to show an atom losing an electron. When an atom gains an electron, it gains a charge. Therefore, the atom has more electrons and is. A negative ion is called an. Complete the diagram to show an atom losing an electron. To determine the electric charge of an ion, you must know the between protons and electrons. If there are more, the ion is. A is used to denote s positive ion. If there are more, the ion is. A is used to denote a negative ion. Write the charge as a to the right of the atom. If the ion has a +1 charge, simply write. If the ion has a -1 charge, simply write. Example: A sodium atom has 11 protons and 10 electrons. How do you denote the charge on this atom? Example: An oxygen atom has 8 protons and 10 electrons. How do you denote the charge on this atom?
An atom wants to gain or lose electrons in order to have a complete shell. An atom that has only one or two valance electrons tends to those electrons and become a ion. What happens to lithium and why? An atom that has nearly a full valance shell tends to electrons and become a ion. What happens to fluorine and why? PERIODIC TABLE There are more than 100 different. All the known elements are organized in a table. This table is called the of. The periodic table displays each in a box. In most periodic tables, each box gives 4 pieces of information about the elements: 1. 2. 3. 4. Elements are presented in the periodic table by order of atomic. Elements are arranged in rows and columns in the periodic table. The rows are called. The columns are called. dictates how elements are organized in the rows and columns of the periodic table. Elements with the same number of electrons are placed in the same column. Elements with the same number of are placed in the same row. This organization explains the of the periodic table. There are four major types of elements in the periodic table: 1. 2. 3. 4. Outline and label the major types of elements in the table.
METALS Most elements are. What are characteristics of metals? What are some examples of metals? NONMETALS make up the majority of the universe. What are characteristics of nonmetals? What are some examples of nonmetals? Hydrogen is a even though it is located on the periodic table where most of the metals are found. METALLOIDS have characteristics in-between metals and nonmetals. Metalloids are and have a appearance. Although they look like metals, most metalloids are, not and fair. What are the 6 commonly recognized metalloids? 1. 2.
3. 4. 5. 6. and/or are sometimes included. NOBEL GASES and are sometimes included as metalloids. Nobel gases are, elements. As their name suggests, Nobel gases are at room temperature. Nobel gases are conductors. What are the 6 Nobel gases? 1. 2. 3. 4. 5. 6. PERIODIC TABLE GROUPS Recall: Elements in the same group have the same number of electrons. The number of valance electrons is easy to determine for groups 1, 2 and 13 through 18. Elements in group 1 have valance electron, elements in group 2 have valance electrons and so on. There are to this pattern in the center block of elements and to the rows of elements below the table. These elements are called metals. Transitional metals have electron configuration. Electrons are added to the to last orbital instead of the shell. Some groups have specific names because they share similar properties: 1. 2. 3. 4. 5. Elements in these groups share similar because they have the same number of electrons. Outline and label the periodic table groups in the periodic table below.
Describe each of the groups in the table below. Group Characteristics Alkali Metals Alkaline Earth Metals Transitional Metals Halogens Nobel Gases F BLOCK ELEMENTS
Below the period table are two rows of elements. These rows make up the of the periodic table. Elements in the F block are of the periodic table, but it s easier to them on the bottom of the table. Each row is considered a of elements. The first row is called the series. The second row is called the series. LATHANIDE SERIES The lanthanide series includes chemical elements with atomic numbers through. All of these elements are shiny,. These elements are. What are some uses for Lanthanide elements? ACTINIDE SERIES The actinide series include chemical elements with atomic numbers through. All of these elements are. Some of the actinide elements are - they are not found nature. Elements with atomic numbers through are synthetic elements. What are some uses for Actinide elements? SYNTHETIC ELEMENTS There are other elements in the periodic table. In total, there are synthetic elements. These elements have atomic numbers through. Synthetic elements do not occur on Earth. All synthetic elements were made in a. All synthetic elements are and. They decay, some in only a few hundred. Some elements, such as and, are synthetically made. However, they are not purely synthetic. They exist in very minute quantities on Earth. PERIODIC TABLE TRENDS There are patterns to the properties of elements in the periodic table. These patterns are called. ATOMIC RADIUS What is atomic radius? How does atomic radius change as you move down a column? How does atomic radius change as you move across a row? ELECTRONEGATIVITY
What is electronegativity? How does electronegativity change as you move across a row? How does electronegativity change as you move up a column? IONIZATION ENERGY What is ionization energy? How does ionization energy change as you move across a row? How does ionization energy change as you move up a column? METALLIC CHARACTER Elements, except, on the left side of the periodic table are. These elements have character. character refers to characteristics of metals. What are 4 characteristics of metals? 1. 2. 3. 4. Metalloids have some character. Nonmetals do not have character, which is why they are called nonmetals. How does metallic character change as you move across the periodic table? Summarize the periodic table trends on the table below
. Reflection Questions 1. Summarize how the model of an atom changed over the years. 2. What are the similarities and differences between a proton, neutron and electron? 3. What happens when the amount of protons, neutrons or electrons change in an atom? 4. Summarize some of the important trends of the periodic table of elements.