chap 4 + 5

Created by

Bernice Lee

Cards (60)

In which group of the periodic table are noble gases found?
Group 18
Why are noble gases considered stable and unreactive?
They have a fully-filled valence shell
What type of structure does a pure metal have in the solid state?
Giant metallic (lattice) structure
What is the electron configuration of helium?
Duplet configuration (2 electrons)
How are the atoms arranged in a pure metal?
In layers
What is the electron configuration of all other noble gases besides helium?
Octet configuration (8 electrons)
What are ions formed from?
When an atom loses or gains electrons
What happens to the layers of atoms in a pure metal when a force is applied?
The layers can slide over each other easily
What are positive ions called?
Cations
Why are many pure metals considered soft?
Because the layers of atoms can slide over each other easily
What are negative ions called?
Anions
How many electrons do ions typically lose or gain?
They either lose or gain 3 electrons
What characterizes the atoms in an alloy?
The atoms are of different sizes
Between which types of elements do ions typically form?
Between metals and nonmetals
What are ions with 2 or more covalently bonded atoms called?
Polyatomic ions
What holds oppositely charged ions together in ionic bonds?
Strong electronic forces of attraction
How does the size of atoms in an alloy affect the arrangement of layers? 
It disrupts the orderly arrangement of the layers of atoms
What is the effect of applying force to an alloy compared to a pure metal?
The layers of atoms in an alloy cannot slide over each other easily
How should the chemical formula of an ionic compound be written?
Positively charged ions must be before negatively charged ions
What charge does magnesium form as an ion?
Mg2+ (charge of 2+)
Why are alloys harder and stronger than pure metals?
Because the layers of atoms cannot slide over each other easily
What charge does chlorine form as an ion?
Cl- (charge of 1-)
What are the main differences between elements, compounds, and mixtures?
**Elements**: Pure substances, one type of atom, fixed melting/boiling point.
**Compounds**: Made from more than one element, chemically bonded, fixed ratio by mass, fixed melting/boiling point.
**Mixtures**: Not in specific ratios, can be separated physically, no chemical reaction during formation.
What is the chemical formula for magnesium chloride?
MgCl2
What is an element? 
A pure substance that cannot be broken down into anything else
What types of atoms can elements consist of?
Individual atoms or molecules
What is a giant ionic lattice structure (GILS)?
A giant structure of ions
Regular, repeating arrangement of ions
Formed by strong electrostatic forces of attraction
What is a characteristic of the melting/boiling point of elements?
They have a fixed melting/boiling point
Why do ionic compounds have very high melting and boiling points?
Because a large amount of energy is required to overcome strong electrostatic forces of attraction
Are ionic compounds usually soluble in water?
Yes, they are usually soluble in water
Why do ionic compounds conduct electricity in aqueous and molten states?
Because the ions are free to move about in these states
How are compounds formed? 
Via chemical reactions
What is a compound?
A pure substance made from more than one element
How are the elements in a compound bonded?
All elements are chemically bonded together
Why do ionic compounds not conduct electricity in solid state?
Because the ions are held in fixed positions and cannot move
What is the significance of the fixed ratio by mass in compounds?
It indicates how elements are bonded together
What is a covalent bond?
A bond formed when two or more nonmetal atoms share a pair of electrons
What is the purpose of forming covalent bonds?
To achieve a fully filled valence shell
How can each compound be represented? 
By a chemical formula
What is a molecule?
A group of two or more atoms joined together by covalent bonds