Question

galaxy ngc 8756, distance: 3 billion lightyears
age: 9 billion years
wavelength: 400 nm
energy: 3 ev
uv
500 nm
2.5 ev
blue
600 nm
2 ev
green
700 nm
1.7 ev
red
800 nm
1.5 ev
infrared

1. elements present oxygen, hydrogen
2. circle the heaviest element you listed in number 1
3. draw a neutral atom of the heaviest element below: _p _n

Explanation:

Step1: Identify heavier element

Oxygen (O) has an atomic number of 8 and hydrogen (H) has an atomic number of 1. Oxygen is heavier.

Step2: Draw oxygen atom

A neutral oxygen - atom has 8 protons (P), 8 neutrons (N) in the nucleus and 8 electrons in 2 electron - shells (2 in the first shell and 6 in the second shell).

Answer:

1. Elements present: Oxygen, Hydrogen
2. Circle oxygen
3. In the nucleus, write 8 for the number of protons (P) and 8 for the number of neutrons (N). Draw 2 electron - shells around the nucleus, with 2 electrons in the inner shell and 6 electrons in the outer shell.