(b) mass number
(c) number of electron shells
(d) number of valence electrons
Answer;
- (d) number of valence electrons
The elements in Group 2 have similar chemical properties because each atom of these elements has the same number of valence electrons.
Explanation;
-Group 2 elements are also called alkaline earth metals, such as calcium, magnesium, strontium, barium , etc.
-These metals have a valency of two, which means they have two electrons in the outermost energy shell. Therefore; they react by loosing two electrons to form a stable configuration or an octet configuration. They are highly metallic and are good conductors of electricity.
Answer:
m Br = 439.472 g
Explanation:
mass Br = ?
∴ mol Br = 5.50 mol
∴ molar mass Br 79.904 g/mol
mass = (mol)*(g/mol)
⇒ m Br = (5.50 mol)*(79.904 g/mol)
⇒ m Br = 439.472 g
The equation we need to use to solve this is: c=λν
c is the speed of light (2.998 x 10^8 m/s)
λ is the wavelength, which we're gonna solve for
ν is the frequency ( 2.4 x 10^14 Hz )
First, plug in the values we were given into the equation
2.998 x 10^8 m/s= (λ)(2.4 x 10^14 Hz)
Next, divide both sides of the equation by 2.4 x 10^14 Hz to solve for the wavelength (λ)
λ= 1.249166667 x 10^-6 m
Round to 2 significant figures
λ= 1.2 x 10^-6 m