Questions and Answers
Group 7A of the periodic table contains the most reactive:
One twelfth the mass of a carbon-12 atom is used to define:
atomic mass unit
The unit for atomic mass is:
amu
The usefulness of Mendeleev's periodic table was confirmed by:
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In a periodic table, a set of properties repeats from:
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As you move from left to right across a periodic table, the number of valence electrons:
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Compared with Group 2A elements, Group 6A elements have:
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The tendency of an element to react is closely related to what?
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List the Group 1A elements from the most reactive to the least reactive.
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List the Group 7A elements from the most reactive to the least reactive.
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Which element is found in most of the compounds in your body except for water?
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Mendeleev's organized elements in his periodic table in order of increasing:
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Mendeleev's periodic table was useful because it enabled scientists to predict properties of unknown:
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Boron is one block to the left of carbon in the periodic table. The atomic number of carbon is 6. The atomic number of boron is:
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The atomic mass unit (amu) is defined as one twelfth the mass of a:
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Elements can be classified as metals, nonmetals, and:
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From left to right across a period in the periodic table, element 4, beryllium, has two valence electrons. Element 5, boron, has:
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Element 3, lithium, has one valence electron, and element 4, beryllium, has two valence electrons. Element 5, boron has:
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In general, an alkali metal will be more reactive than an alkaline earth metal in the same period.
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Although they are called neon light, they can contain any noble gas.
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Reactive elements, such as alkali metals and halogens, are found in nature only as:
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Suppose you are looking at elements in the periodic table in this order: element 23, element 24, element 25, element 26, and so on. Are you looking across a period or down a group?
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What determines an element's chemical properties?
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In the periodic table, there are two numbers in the block for the element potassium (K): 19 and 39.098. What do these two numbers represent?
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Boron (B), silicon (Si), germanium (Ge), and arsenic (As) have properties that fall between those of metals and nonmetals. What common label could you apply to these elements?
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Period 5 of the periodic table begins with element 37 and ends with element 54. Which of the following elements is most likely to be a transition metal?
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Element X has one valence electron, element Y has one valence electron, and element Z has five valence electrons. Which two of these elements are most likely to have similar properties? Explain your answer.
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Among the alkaline earth metals in Group 2A, which is more reactive - beryllium (element A) or strontium (element 38)?
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Sodium chloride is a compound of sodium and chlorine. Which of these elements is the alkali metal, and which is the halogen?
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Study Notes
Key Characteristics of Groups in the Periodic Table
- Group 7A consists of the most reactive nonmetals.
- Group 1A elements arranged from most to least reactive: Francium, Cesium, Rubidium, Potassium, Sodium, Lithium.
- Group 7A elements ordered by reactivity: Fluorine, Chlorine, Bromine, Iodine, Astatine.
- Group 6A elements have more valence electrons than Group 2A elements.
Atomic Mass and Definitions
- Atomic mass unit (amu) is defined as one-twelfth the mass of a carbon-12 atom.
- The unit of atomic mass is amu.
- The atomic number represents the number of protons in an element's nucleus.
Mendeleev and the Periodic Table
- Mendeleev organized elements in the periodic table by increasing mass.
- His periodic table was confirmed useful through the discovery of elements with predictive properties.
- Enabled predictions of unknown element properties.
Properties of Elements
- As you move left to right in the periodic table, the number of valence electrons increases.
- The tendency of an element to react is closely related to its number of valence electrons.
- Elements are classified as metals, nonmetals, and metalloids, with boron, silicon, germanium, and arsenic recognized as metalloids.
Reactivity in Elements
- Alkali metals are generally more reactive than alkaline earth metals within the same period.
- Reactive elements, such as alkali metals and halogens, exist only in nature as compounds.
- Beryllium has two valence electrons; boron, with three valence electrons, shows increasing nonmetallic properties.
Transition Metals and Group Information
- Cadmium is identified as a transition metal among elements in period 5, sandwiched between strontium and iodine.
- When comparing valence electrons, elements X (one valence electron) and Y (one valence electron) share similar properties.
Specific Elements and Compounds
- Carbon is a vital element found in most compounds in the human body, excluding water.
- Sodium chloride is composed of sodium (alkali metal) and chlorine (halogen).
- Strontium (element 38) is more reactive than beryllium (element A) among alkaline earth metals.
Periodic Table Layout
- Elements can be examined across periods or down groups; for example, elements 23 to 26 are looked at across a period.
- Elements in the periodic table display repeating properties from row to row, indicating structured relationships among different element groups.
Studying That Suits You
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Test your knowledge of Chapter 5 of chemistry focusing on the periodic table through these engaging flashcards. Each card covers essential concepts such as atomic mass, reactivity of nonmetals, and the historical significance of Mendeleev's periodic table.