Answer:
The spectra of the Sun and stars exhibited bright and dark lines called Fraunhofer lines. These were shown to be caused by elements emitting or absorbing light at specific wavelengths. Because each element emits or absorbs light only at specific wavelengths, the chemical composition of stars can be determined.
Answer:The two-party system came into being because the structure of U.S. elections, with one seat tied to a geographic district, tends to lead to dominance by two major political parties. ... Plurality voting has been justified as the simplest and most cost-effective ... After the election is over, supporters experience remorse when
Explanation: hope u get it right
Answer:
En el caso del sodio, la valencia es 1, ya que tiene un solo electrón de valencia, si pierde un electrón se queda con el último nivel completo.
Explanation:
Grupo de la tabla periódica Electrones de valencia
Grupo 14 (IV) (Grupo del carbono) 4
Grupo 15 (V) (Grupo del nitrógeno ) 5
<u>Answer:</u> The mass of ice is 
<u>Explanation:</u>
We are given:
Area of Antarctica =
(Conversion factor:
)
Height of Antarctica with ice = 7500 ft.
Height of Antarctica without ice = 1500 ft.
Height of ice = 7500 - 1500 = 6000 ft =
(Conversion factor: 1 ft = 30.48 cm)
To calculate mass of ice, we use the equation:

We are given:
Density of ice = 
Volume of ice = Area × Height of ice = 
Putting values in above equation, we get:

Hence, the mass of ice is 
Answer:
20
Explanation:
Hi there!
We need to find the atomic number of an atom that has 20 protons and 20 neutrons
the atomic number of an atom is equivalent to the amount of protons an atom has, as the number of protons determines what element an atom is.
Since the atom has 20 protons, the atomic number of the said atom is <u>20</u>
Hope this helps!