Question

magnesium (mg) has an atomic number of 12. what is the ground - state electron configuration of magnesium?

a 1s²1p⁶2s²2p²
b 1s²1p⁶1d⁴
c 1s²2s²2p⁶3s²
d 1s²2s²2p⁶2d²

pregunta 12 (5 puntos)
(02.04 lc)
which type of electromagnetic radiation has a lower frequency than infrared radiation?

a gamma rays
b visible light
c x - rays
d microwaves

pregunta 13 (5 puntos)
(02.04 mc)
compared to infrared radiation, an electromagnetic wave that has a lower frequency will also have a
a long wavelength and lower speed
b shorter wavelength and lower speed
c shorter wavelength and equal speed
d longer wavelength and equal speed

Explanation:

1. For the electron - configuration of magnesium (atomic number 12), electrons fill orbitals in order of increasing energy following the Aufbau principle. The first two electrons go in the 1s orbital (1s²), the next two in the 2s orbital (2s²), the next six in the 2p orbital (2p⁶), and the last two in the 3s orbital (3s²), so the ground - state electron configuration is 1s²2s²2p⁶3s².
2. In the electromagnetic spectrum, the order of increasing frequency is: radio waves < microwaves < infrared < visible light < ultraviolet < X - rays < gamma rays. So microwaves have a lower frequency than infrared radiation.
3. The relationship between the speed (c), frequency (ν), and wavelength (λ) of an electromagnetic wave is given by c = νλ. Since the speed of electromagnetic waves in a vacuum is constant (c = 3×10⁸ m/s), if the frequency is lower, the wavelength must be longer.

Answer:

1. c. 1s²2s²2p⁶3s²
2. d. Microwaves
3. d. longer wavelength and equal speed