8.1 Arrangement of Elements (Cambridge (CIE) O Level Chemistry): Flashcards
Exam code: 5070
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- FrontThe Periodic Table
What do groups in the Periodic Table tell you about an element?
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What do groups in the Periodic Table tell you about an element?
Groups are the vertical columns and show how many outer electrons an element has. For example, all Group VII elements have 7 outer electrons in their outer shell.
A metal in Group II will ______ two electrons when forming an ion, giving it a charge of ______.
A metal in Group II will lose two electrons when forming an ion, giving it a charge of 2+.
What do periods in the Periodic Table tell you about an element?
Periods are the horizontal rows and show the number of occupied electron shells an element has. For example, all elements in Period 3 have 3 electron shells.
Why do elements in the same group have similar chemical properties?
Elements in the same group have the same number of outer electrons. Since it is the outer electrons that interact during chemical reactions, elements in the same group react in similar ways.
True or False?
Elements in the Periodic Table are arranged in order of increasing mass number.
False.
Elements are arranged in order of increasing atomic number (proton number), not mass number.
A non-metal in Group VII will ______ one electron when forming an ion, giving it a charge of ______.
A non-metal in Group VII will gain one electron when forming an ion, giving it a charge of 1−.
What is the valency of an element?
Valency is the combining power of an element: the number of electrons its atoms lose, gain or share when forming compounds. For example, carbon (Group IV) has a valency of 4.
Metallic character ______ as you move across a period from left to right, and ______ as you move down a group.
Metallic character decreases as you move across a period from left to right, and increases as you move down a group.
How does an element's electronic configuration reveal its period and group?
The number of occupied shells equals the period number (number of digits), and the number of outer electrons equals the group number (last number). For example, chlorine (2,8,7) is in Period 3, Group VII.
What is a metalloid?
A metalloid (or semi-metal) is an element that displays properties of both metals and non-metals. Metalloids lie along the boundary between metals and non-metals on the Periodic Table.
True or False?
Elements in the same group have similar chemical properties because they have the same number of electron shells.
False.
Elements in the same group have similar properties because they have the same number of outer electrons, not the same number of shells.
Lithium has the electronic configuration 2,1. This means lithium is in Period ______ and Group ______.
Lithium has the electronic configuration 2,1. This means lithium is in Period 2 and Group I.
How can the Periodic Table be used to predict the properties of an element?
Elements in the same group have similar properties, so trends within a group (such as reactivity, melting point or density) can be used to predict the behaviour of other elements in that group.
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