Question

directions: use a periodic table to draw a bohr model of the following atoms.
hydrogen
atomic number
atomic mass
number of protons
number of electrons
number of neutrons
helium
atomic number
atomic mass
number of protons
number of electrons
number of neutrons
boron
atomic number
atomic mass
number of protons
number of electrons
number of neutrons

Explanation:

Step1: Recall atomic number definition

Atomic number \(Z\) is the number of protons. For Hydrogen (\(H\)): \(Z = 1\), for Helium (\(He\)): \(Z=2\), for Boron (\(B\)): \(Z = 5\).

Step2: Use atomic mass formula

Atomic mass \(A\approx\) number of protons (\(p\))+ number of neutrons (\(n\)). For Hydrogen (most common isotope, \(A = 1\)): \(n=A - p=1 - 1=0\). For Helium (\(A = 4\)): \(n=4 - 2=2\). For Boron (\(A = 11\)): \(n=11 - 5 = 6\).

Step3: Apply charge - neutrality

In a neutral atom, number of electrons (\(e\))= number of protons (\(p\)). So for \(H\): \(e = 1\), for \(He\): \(e=2\), for \(B\): \(e = 5\).

Answer:

Atom	Atomic Number	Atomic Mass	Number of Protons	Number of Electrons	Number of Neutrons
Helium	\(2\)	\(4\)	\(2\)	\(2\)	\(2\)
Boron	\(5\)	\(11\)	\(5\)	\(5\)	\(6\)

For the Bohr - model drawings:

• Hydrogen: In the nucleus, \(p = 1\), \(n=0\). One electron in the first (and only, for \(H\)) electron shell (\(n = 1\) shell, which can hold up to \(2\) electrons).
• Helium: In the nucleus, \(p = 2\), \(n = 2\). Two electrons in the \(n = 1\) shell (which is full as it can hold \(2\) electrons).
• Boron: In the nucleus, \(p = 5\), \(n = 6\). Two electrons in the \(n = 1\) shell (capacity \(2\)) and three electrons in the \(n=2\) shell (capacity \(8\)).