Question

chemistry: atomic number and mass number
complete the following chart and answer the questions below.
element name atomic number number of protons number of neutrons mass number
carbon 12 6 6 12
oxygen 8 8 8 16
hydrogen 1 1 0 1
carbon 6 6 8 14
hydrogen 2 2 2 4
nitrogen 7 7 7 14
hydrogen 1 1 1 2
uranium 92 92 146 238
cesium 82
sodium 11 11 12 23
47 108
tungsten 74 74 110 184
45 80
24 52
europium 63 63 89 152
silver 107
osmium 76 76 114 190

Explanation:

Step1: Recall atomic number - proton relationship

The atomic number of an element is equal to the number of protons in its nucleus. So we can fill in the number - of - protons column directly from the atomic number column.

Step2: Recall mass number formula

The mass number is the sum of the number of protons and neutrons in the nucleus. So for each row, we can calculate the missing value among atomic number, number of neutrons, or mass number using the formula $Mass\ number=Number\ of\ protons + Number\ of\ neutrons$.

Element Name	Atomic Number	Number of Protons	Number of Neutrons	Mass Number
oxygen	8	8	8	16
hydrogen	1	1	0	1
carbon	6	6	8	14
hydrogen	2	2	2	4
nitrogen	7	7	7	14
hydrogen	1	1	1	2
uranium	92	92	146	238
cesium	55	55	82	137
sodium	11	11	12	23
silver	47	47	61	108
tungsten	74	74	110	184
bromine	35	35	45	80
chromium	24	24	28	52
europium	63	63	89	152
silver	47	47	60	107
osmium	76	76	114	190

Answer:

The completed table is shown above. (Note: For cesium, the atomic number is 55 which was missing in the original table. For silver with mass number 107, number of neutrons is calculated as $107 - 47=60$ and for silver with mass number 108, number of neutrons is $108 - 47 = 61$. Also, for the blank rows with just neutron and mass - number values given, element names were assumed based on common knowledge of elements with those atomic characteristics. For example, for atomic number 35 and mass number 80, it is bromine; for atomic number 24 and mass number 52, it is chromium)