Question

question 9. complete the table for the following elements.

element	number of protons	number of electrons	number of neutrons	atomic number	mass number
sodium		11	12
bromine	35		45
yttrium				39	89
arsenic		33			75
actinium					227

Explanation:

Step1: Recall atomic - related rules

In a neutral atom, the number of protons = the number of electrons. The atomic number is equal to the number of protons, and the mass number = number of protons + number of neutrons.

Step2: Calculate for Manganese

Since number of protons = 25, for a neutral atom, number of electrons = 25. Atomic number = 25. Mass number = 25 + 30=55.

Step3: Calculate for Sodium

Number of electrons = 11, so number of protons = 11. Atomic number = 11. Mass number = 11 + 12 = 23.

Step4: Calculate for Bromine

Number of protons = 35, so for a neutral atom, number of electrons = 35. Atomic number = 35. Mass number = 35+45 = 80.

Step5: Calculate for Yttrium

Atomic number = 39, so number of protons = 39. For a neutral atom, number of electrons = 39. Number of neutrons = 89 - 39 = 50.

Step6: Calculate for Arsenic

Number of electrons = 33, so number of protons = 33. Atomic number = 33. Number of neutrons = 75 - 33 = 42.

Step7: Calculate for Actinium

Mass number = 227. Let the number of protons be \(x\). Since atomic number is not given directly, assume it is \(x\). For a neutral atom, number of electrons = \(x\). Let number of neutrons be \(y\). We know mass number = number of protons+number of neutrons. But without more information about number of neutrons or protons, we can't fill all the blanks precisely. However, if we assume a neutral - atom, and since we know mass number = 227, and usually we can find atomic number from periodic table (Actinium's atomic number is 89), then number of protons = 89, number of electrons = 89, and number of neutrons = 227 - 89 = 138.

Answer:

Element	Number of Protons	Number of Electrons	Number of Neutrons	Atomic Number	Mass Number
Sodium	11	11	12	11	23
Bromine	35	35	45	35	80
Yttrium	39	39	50	39	89
Arsenic	33	33	42	33	75
Actinium	89	89	138	89	227