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Mass |
Mendeleev arranged the known chemical elements in a table according to increasing… |
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Unknown element he predicted would have properties similar to those of aluminum |
Mendeleev gave the name eka-aluminum to a (an) |
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Mass number |
Moving from left to right across a row of the periodic table, which of the following values increase by exactly one from element to element? |
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Carbon-12 atom. |
The standard on which the tomic mass unit is based is the mass of a |
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a weighted average of the masses of the elemnt’s isotopes |
The atomic mass of an element is |
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gases |
At room temperature, none of the metals are |
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Most metals are brittle |
Which general statement does NOT apply to metals? |
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Nonmetal bromine |
Two highly reactive elements in Period 4 are the metal potassium and the |
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one or seven valence electrons |
Atoms of the most reactive elements tend to have… |
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Two |
An alkali metal has one valence electron, while an alkaline earth metal has |
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They are similar to noble gases. |
Which statement is NOT true about the elements fluorine, chlorine, and iodine? |
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decreases from top to bottom within the group |
Among the alkali metals, the tendency to react with other substances |
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F(fluorine) |
What halogen is most likely to react? |
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Argon |
To keep them from reacting, some highly reactive elements are stored in |
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Sodium |
Which element is found in nature only in compounds? |
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Column |
When Mendeleev organize elements in his periodic table in order of increasing mass, elements with similar properties were in the same |
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low |
Mendeleev predicted that the undiscovered element he called eka- aluminum would have a _____ melting point |
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periodic law |
The pattern of repeating properties of elements revealed in the periodic table is known as the ____ |
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Nitrogen |
Fertilizers usually contains two elements from group 5A, which are _____ and phosphorus |
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water |
One way to demonstrate reactivity among the alkaline earth metals, Group 2A, is to observe what happens when they are placed in ____ |
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He wanted to organize information about the elements for a textbook he waas writing. |
Why did Mendeleev want to make a periodic table of the elements |
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Atomic number, number or protons in each element. |
What do the whole numbers on the periodic table represent? |
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Selium is a nonmetal |
Selenium has six valence electrons, while rubidium has one valence electron. Identify each element as a metal or a nonmetal |
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Chlorine |
Silicon and chlorine are both in Period 3. Which is the more reactive element |
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Sulfur is not a highly reactive element under ordinary conditions. |
Sulfur is often found in nature as an element, not combined with other elements in a compound. What does this fact tell you about the reactivity of sulfur? |
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You could store the compound in a jar filled with a noble gas such as argon. Students may also recall that reactive elements are stored under oil. |
In a laboratory procedure, you form a highly reactive compound. How could you store the compound so that it will not react? |
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You could see which piece conducts an electric current or which piece is a better conductor of heat. |
In science lab, your teacher gives you two small pieces of matter and tells you that one piece is a metal and one is a nonmetal. Without changing the size or shape of the pieces, how could you test them to determine which is the metal? |
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The properties repeat at regular intervals |
How are the octaves on a keyboard on analogy for the periods in a periodic table? |
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Lithium is an alkali metal in Group 1A. Alkali metals are the most reactive metals. Neon is a noble gas in Group 8A. Noble gases are highly unreactive nonmetals. |
Although lithium and neon are both in Period 2 of the periodic table, they have very different properties, Explain how this is possible. |
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row to row |
In a periodic table, a set of properties repeats from |
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the discovery of elements with predicted properties |
The usefulness of Mendeleev’s periodic table was confirmed by |
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atomic mass unit |
One-twelfth the mass of a carbon-12 atom is used to define a (an) |
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Take a weighted average of the masses of the isotopes present in nature |
How is the atomic mass of an element determined? |
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sodium,chromium, copper |
Which list of elements contains only metals? |
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Silicon is a better conductor of an electric current than sulfur is |
Which statement is true about the metalloid silicon? |
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Most reactive metals |
The column on the far left of the periodic table contains the |
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increases |
As you move from left to right across a period, the number of valence electrons |
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More Valence Electrons |
Compared with Group 1A elements, Group 7A elements have |
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the number of valence electrons in atoms of the elements |
The tendency of an element to react chemically is closely related to |
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Cs(Cesium) |
Which of these Group 1A elements is the most reactive? |
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F (fluorine) |
Which of these Group 7A elements is the most reactive? |
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Helium and neon |
Which of the following gases emit color when an electric current is applied? |
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Carbon |
Which element is found in most of the compound in your body except for water? |
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Metals |
Mendeleev organized elements in his periodic table in order of increasing |
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elements |
Mendeleev’s periodic table was useful because it enabled scientists to predict properties of unknown |
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15 |
Phosphorus is one block to the left of sulfur in the periodic table. The atomic # of sulfur is 16. The atomic number of phosphorus is |
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Carbon |
The atomic mass unit (amu) is defined as one-twelfth the mass of a _____-12 atom |
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metalloids |
Elements can be classified as metals, nonmetals, and |
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metallic/nonmetallic |
From left to right across a period in the periodic table, elements become less ______ and more _______ |
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three |
Element 3, lithium, has one valence electron, and element 4, beryllium, has two valence electrons. Element 5, boron, has _____ valence electrons |
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Alkali |
In general, a _____ metal will be more reactive than an alkaline earth metal in the same period. |
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Neon |
Although they are called _____ lights, they can contain any noble gas. |
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Mendeleev predicted the properties of these undiscovered elements from data in his periodic table, when the elements sere discovered their actual properties were found to be a close match to those Mendeleev had predicted. Their discovery provided evidence of the usefulness of Mendeleev’s periodic. |
Why were the elements gallium (Ga) scandium (Sc) and germanium (Ge) important to Mendeleev? |
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