science 5
a
Based on their group in the periodic table, how many valence electrons do atoms of calcium, Ca, and magnesium, Mg have? a. Both elements are in Group 2 and have two valence electrons. b. Mendeleev's periodic table had predicted the discovery and properties of germanium. c. They are found in the same group, or column.
a
How could a flourine atom change to satisfy the octet rule? a. To satisfy the octet rule, the atom needs to have eight valence electrons. To do this, the flourine atom could gain one valence electron. b. Unreactive elements are those that are very stable and rarely undergo chemical changes. Each has a full set of valence electrons, with no partly-filled energy levels. c. A lithium has 1 valence electron. It loses this electron to become an ion with a charge of 1+.
c
Lithium has one valence electron. What type of ion will it form? a. The lithium forms an ion with the charge of 1+, so the symbol for the ion is Li+. b. A lithium has 1 valence electron. It loses this electron to become an ion with a charge 1-. c. A lithium has 1 valence electron. It loses this electron to become an ion with a charge 1+.
c
Lithium has one valence electron. What type of ion will it form? a. To satisfy the octet rule, the atom needs to have eight valence electrons. To do this, the flourine atom could gain one valence electron. b. Unreactive elements are those that are very stable and rarely undergo chemical changes. Each has a full set of valence electrons, with no partly-filled energy levels. c. A lithium has 1 valence electron. It loses this electron to become an ion with a charge of 1+.
a
What is the symbol of a lithium ion if the symbol for lithium atom is Li+? a. The lithium forms an ion with the charge of 1+, so the symbol for the ion is Li+. b. A lithium has 1 valence electron. It loses this electron to become an ion with a charge 1-. c. A lithium has 1 valence electron. It loses this electron to become an ion with a charge 1+.
c
Where elements with similar chemical properties found found in the periodic table? a. Both elements are in Group 2 and have two valence electrons. b. Mendeleev's periodic table had predicted the discovery and properties of germanium. c. They are found in the same group, or column.
a
Where in an atom can you find electrons with the least energy? a. These electrons are located in the energy level that is closest to the nucleus. b. Valence electrons are the electrons in the outermost energy level, and most atoms also have electrons in lower energy levels. c. A lithium atom has 1 valence electron. It loses this electron to become an ion with a charge of 1+.
b
Why are helium, neon, and argon all unreactive gases? a. To satisfy the octet rule, the atom needs to have eight valence electrons. To do this, the flourine atom could gain one valence electron. b. Unreactive elements are those that are very stable and rarely undergo chemical changes. Each has a full set of valence electrons, with no partly-filled energy levels. c. A lithium has 1 valence electron. It loses this electron to become an ion with a charge of 1+.
b
Why did the discovery of germanium show the value of Mendeleev's periodic table? a. Both elements are in Group 2 and have two valence electrons. b. Mendeleev's periodic table had predicted the discovery and properties of germanium. c. They are found in the same group, or column.
b
Why is the number of valence electrons less than the number of electrons for most atoms? a. These electrons are located in the energy level that is closest to the nucleus. b. Valence electrons are the electrons in the outermost energy level, and most atoms also have electrons in lower energy levels. c. A lithium atom has 1 valence electron. It loses this electron to become an ion with a charge of 1+.
