Describe how Mendeleev arranged elements in the first periodic table. Explain how elements are arranged in the modern periodic table.

Section 1 Arranging the Elements Objectives Describe how Mendeleev arranged elements in the first periodic table. Explain how elements are arranged in the modern periodic table. Compare metals, nonmetals, and metalloids based on their properties and on their location in the periodic table. Describe the difference between a period and a group.

Section 1 Arranging the Elements Discovering a Pattern In 1869, Russian chemist Dmitri Mendeleev arranged the elements in order of increasing atomic mass. Periodic Properties of the Elements When the elements are arranged in order of increasing atomic mass, those that had similar properties occurred in a repeating pattern. These repeating patterns are periodic, meaning that they happen at regular intervals.

Section 1 Arranging the Elements Discovering a Pattern, continued Predicting Properties of Missing Elements Mendeleev s arrangement had gaps in its pattern. Mendeleev predicted that elements yet to be found would fill these gaps. He also predicted the properties of the missing elements. By 1886, all of the gaps had been filled and Mendeleev s predictions were right.

Section 1 Arranging the Elements Changing the Arrangement A few elements properties did not fit in the pattern of Mendeleev s table. In 1914, British scientist Henry Moseley found the number of protons the atomic number in an atom. When the elements were arranged by atomic number, they fit the pattern in Mendeleev s table.

Section 1 Arranging the Elements

Section 1 Arranging the Elements The Periodic Table and Classes of Elements Elements are classified as metals, nonmetals, and metalloids, according to their properties. The number of electrons in the outer energy level of an atom is one characteristic that helps determine which category an element belongs in. The zigzag line on the periodic table can help you recognize which elements belong in which category.

Section 1 Arranging the Elements The Periodic Table and Classes of Elements, continued Metals are found to the left of the zigzag line. Atoms of most metals have few electrons in their outer energy level. Most metals are shiny, ductile, malleable, and are good conductors of electric current and thermal energy.

Section 1 Arranging the Elements The Periodic Table and Classes of Elements, continued Nonmetals are found to the right of the zigzag line. Atoms of most nonmetals have an almost complete set of electrons in their outer energy level. Nonmetals are not shiny, ductile, or malleable, and are poor conductors of electric current and thermal energy.

Section 1 Arranging the Elements The Periodic Table and Classes of Elements, continued Metalloids are the elements that border the zigzag line. Atoms of metalloids have about half of a complete set of electrons in their outer energy level. Metalloids have some properties of metals and some properties of nonmetals. Metalloids are also called semiconductors.

Section 1 Arranging the Elements Decoding the Periodic Table Each Element is Identified by a Chemical Symbol Each square on the periodic table includes an element s name, chemical symbol, atomic number, and atomic mass. For most elements, the chemical symbol has one or two letters. The newest elements have temporary three-letter symbols.

Section 1 Arranging the Elements Decoding the Periodic Table, continued Rows Are Called Periods Each horizontal row of elements is called a period. The chemical and physical properties of elements in a row follow a repeating pattern as you move across the period. Columns Are Called Groups Each vertical column of elements is called a group. Elements in the same group often have similar chemical and physical properties.

Section 2 Grouping the Elements Objectives Explain why elements in a group often have similar properties. Describe the properties of the elements in the groups of the periodic table.

Section 2 Grouping the Elements Group 1: Alkali Metals Alkali metals are elements in Group 1 of the periodic table. Alkali metal properties: group contains metals 1 electron in the outer level very reactive softness, color of silver, shininess, low density

Section 2 Grouping the Elements Group 2: Alkaline-Earth Metals Alkaline-earth metals are elements in Group 2. Alkaline-earth metal properties: group contains metals 2 electrons in the outer level very reactive, but less reactive than alkali metals color of silver, higher densities than alkali metals

Section 2 Grouping the Elements Group 3 12: Transition Metals Transition metals are in Groups 3 12. Some of the transition metals are shown below.

Section 2 Grouping the Elements Group 3 12: Transition Metals, continued Properties of Transition Metals vary widely but include: groups contains metals 1 or 2 electrons in the outer level less reactive than alkaline-earth metals shininess, good conductors of electric current and thermal energy

Section 2 Grouping the Elements Group 3 12: Transition Metals, continued Lanthanides and Actinides Some transition metals from Periods 6 and 7 appear in two rows at the bottom of the periodic table. Elements in the first row are called lanthanides and elements in the second row are called actinides.

Section 2 Grouping the Elements Group 13: Boron Group Aluminum is the most common element from Group 13. Group 13 properties: group contains one metalloid and five metals 3 electrons in the outer level reactive solids at room temperature

Section 2 Grouping the Elements Group 14: Carbon Group Group 14 properties: group contains one nonmetal, two metalloids, and two metals 4 electrons in the outer level reactivity varies among the elements solids at room temperature

Section 2 Grouping the Elements Group 15: Nitrogen Group Group 15 properties: group contains two nonmetals, two metalloids, and two metals 5 electrons in the outer level reactivity varies among the elements solids at room temperature (except for nitrogen, which is a gas)

Section 2 Grouping the Elements Group 16: Oxygen Group Group 16 properties: group contains three nonmetals, one metalloids, and one metal 6 electrons in the outer level reactive solids at room temperature (except for oxygen, which is a gas)

Section 2 Grouping the Elements Group 17: Halogens Halogens are the elements in Group 17. Group 17 properties: group contains nonmetals 7 electrons in the outer level very reactive poor conductors of electric current, never in uncombined form in nature

Section 2 Grouping the Elements Group 18: Noble Gases Noble gases are the elements in Group 18. Group 18 properties: group contains nonmetals 8 electrons in the outer level (except helium, which has 2) unreactive colorless, odorless gases at room temperature

Section 2 Grouping the Elements Hydrogen The properties of hydrogen do not match the properties of any single group, so hydrogen is set apart. a nonmetal 1 electron in the outer level reactive colorless, odorless gas at room temperature, low density

The Periodic Tables Concept Map Use the terms below to complete the concept map on the next slide. elements periods metals electrons nonmetals periodic table groups (families)

The Periodic Table

Standardized Test Preparation Reading Read each of the passages. Then, answer the questions that follow each passage.

Standardized Test Preparation Passage 1 Napoleon III (1808 1873) ruled as emperor of France from 1852 to 1870. Napoleon III was the nephew of the famous French military leader and emperor Napoleon I. Early in his reign, Napoleon III was an authoritarian ruler. France s economy did well under his dictatorial rule, so the French rebuilt cities and built railways. Continued on the next slide

Standardized Test Preparation Passage 1, continued During the 1850s and 1860s, Napoleon III used aluminum dinnerware because aluminum was more valuable than gold. Despite his wealth and French economic prosperity, Napoleon III lost public support and popularity. So, in 1860, he began a series of reforms that allowed more individual freedoms in France.

Standardized Test Preparation 1. What is the meaning of the word authoritarian in the passage? A controlling people s thoughts and actions B writing books and stories C being an expert on a subject D being very wealthy

Standardized Test Preparation 2. Which of the following statements best describes why Napoleon III probably changed the way he ruled France? F He was getting old. G He was unpopular and had lost public support. H He had built as many railroads as he could. I He used aluminum dinnerware.

Standardized Test Preparation 3. According to the passage, in what year did Napoleon III die? A 1808 B 1873 C 1860 D 1852

Standardized Test Preparation Passage 2 Named after architect Buckminster Fuller, buckyballs resemble the geodesic domes that are characteristic of the architect s work. Excitement over buckyballs began in 1985, when scientists projected light from a laser onto a piece of graphite. In the soot that remained, researchers found a completely new kind of molecule! Continued on the next slide

Standardized Test Preparation Passage 2, continued Buckyballs are also found in the soot from a candle flame. Some scientists claim to have detected buckyballs in space. In fact, one suggestion is that buckyballs are at the center of the condensing clouds of gas, dust, and debris that form galaxies.

Standardized Test Preparation 1. Which of the following statements correctly describes buckyballs? A They are a kind of dome-shaped building. B They are shot from lasers. C They were unknown before 1985. D They are named for the scientist who discovered them.

Standardized Test Preparation 2. Based on the passage, which of the following statements is an opinion? F Buckyballs might be in the clouds that form galaxies. G Buckyballs are named after an architect. H Scientists found buckyballs in soot. I Buckyballs are a kind of molecule.

Standardized Test Preparation 3. According to the passage, why were scientists excited? A Buckyballs were found in space. B An architect created a building that resembled a molecule. C Buckyballs were found to be in condensing clouds of gas that form galaxies. D A new kind of molecule was found.

Standardized Test Preparation Interpreting Graphics Use the image of the periodic table below to answer the questions that follow.

Standardized Test Preparation 1. Which of the following statements is correct for the elements shown? A Lithium has the greatest atomic number. B Sodium has the least atomic mass. C Atomic number decreases as you move down the column. D Atomic mass increases as you move down the column.

Standardized Test Preparation 2. Which of the following statements best describes the outer electrons in atoms of the elements shown? F The atoms of each element have 1 outer-level electron. G Lithium atoms have 3 outer-level electrons, sodium atoms have 11, and potassium atoms have 19. H Lithium atoms have 7 outer-level electrons, sodium atoms have 23, and potassium atoms have 39. I The atoms of each element have 11 outer-level electrons.

Standardized Test Preparation 3. The elements featured in the image belong to which of the following groups? A noble gases B alkaline-earth metals C halogens D alkali metals