Chemistry
What characteristics are shared by all alkali metals and alkaline earth metals?
A They conduct electricity very well
B They are strong and shiny
C They form alkaline solutions when mixed with water
D They do not react with water at all
They all conduct electricity very well
The correct answer is C - They form alkaline solutions when mixed with water.
To arrive at this answer, let's understand the characteristics of alkali metals and alkaline earth metals.
1. Alkali Metals: These are the elements in Group 1 of the periodic table, including lithium (Li), sodium (Na), potassium (K), and others. They have certain shared characteristics:
- They are highly reactive and exhibit strong tendencies to lose their outermost electron.
- They have a low density and low melting points.
- They are soft and can be easily cut with a knife.
- They readily form positive ions by losing their outermost electron.
2. Alkaline Earth Metals: These are the elements in Group 2 of the periodic table, including beryllium (Be), magnesium (Mg), calcium (Ca), and others. They also share some common characteristics:
- They are less reactive than alkali metals but still have a strong tendency to lose their two outermost electrons.
- They have higher densities and melting points compared to alkali metals.
- They are harder and more rigid than alkali metals.
Now, looking at the answer choices:
A - They conduct electricity very well: This characteristic is generally true for both alkali metals and alkaline earth metals, but it is not the defining characteristic shared by all of them.
B - They are strong and shiny: While this characteristic is true for many metals, it is not specific to alkali metals and alkaline earth metals.
C - They form alkaline solutions when mixed with water: This is a defining characteristic of both alkali metals and alkaline earth metals. When these metals react with water, they produce hydroxide ions, which results in the formation of alkaline (basic) solutions.
D - They do not react with water at all: This is not accurate. Alkali metals and alkaline earth metals are reactive with water. Alkali metals are more reactive and react vigorously with water, whereas alkaline earth metals react less vigorously but still produce alkaline solutions.
Therefore, the correct answer is C - They form alkaline solutions when mixed with water.