Question

use what you know about the periodic table, atomic number, and atomic mass to complete the table.
element name|atomic symbol|atomic number|# of electrons|# of protons|# of neutrons
lithium|li|?|?|?|4
helium|he|2|2|2|
boron|b|5|5|5|
beryllium|be|4|4|4|
carbon|c|6|6|6|
iron|fe|26|26|30|30
barium|ba|56|56|81|

	12			12
	88
	29

p| |15| | |

	10
		47

Explanation:

Step1: Recall atomic number rule

Atomic number = # of protons = # of electrons (for neutral atoms).

Step2: Calculate for Lithium

Atomic number of Li is 3, so # of electrons = 3, # of protons = 3.

Step3: Recall for Helium

Atomic number of He is 2, # of neutrons = Atomic mass - Atomic number = 4 - 2 = 2.

Step4: Complete other elements

Use same principles for remaining elements.

Answer:

Element Name	Atomic Symbol	Atomic Number	# of electrons	# of Protons	# of neutrons
Helium	He	2	2	2	2
Boron	B	5	5	5	6
Beryllium	Be	4	4	4	5
Carbon	C	6	6	6	6
Iron	Fe	26	26	26	30
Barium	Ba	56	56	56	81
Magnesium	Mg	12	12	12	12
Radium	Ra	88	88	88	138
Copper	Cu	29	29	29	35
Phosphorus	P	15	15	15	16
Neon	Ne	10	10	10	10
Silver	Ag	47	47	47	61