Question

1. how many neutrons do the following elements have?

atomic mass (bottom) - atomic # (top #)

tungsten__ nickel fluorine iron__
sodium__ hydrogen nitrogen silver__
gallium__ bismuth rubidium molybdenum__
argon__ cesium silicon lead__
zirconium__ potassium sulfur iodine__
livermorium__ flerovium copernicium darmstadtium__

Explanation:

Step1: Recall the formula

The number of neutrons \(n\) in an atom is given by \(n = \text{Atomic mass}-\text{Atomic number}\). We need to look up the atomic number and atomic mass (approximate, usually the average atomic - mass from the periodic table) for each element.

Step2: For tungsten (W)

Atomic number \(Z = 74\), average atomic mass \(A\approx183.84\). So the number of neutrons \(n = 184 - 74=110\) (using the whole - number approximation of atomic mass for simplicity).

Step3: For nickel (Ni)

Atomic number \(Z = 28\), average atomic mass \(A\approx58.69\). So \(n = 59 - 28 = 31\).

Step4: For fluorine (F)

Atomic number \(Z = 9\), average atomic mass \(A\approx18.998\). So \(n = 19 - 9=10\).

Step5: For iron (Fe)

Atomic number \(Z = 26\), average atomic mass \(A\approx55.845\). So \(n = 56 - 26 = 30\).

Step6: For sodium (Na)

Atomic number \(Z = 11\), average atomic mass \(A\approx22.989769\). So \(n = 23 - 11 = 12\).

Step7: For hydrogen (H)

Atomic number \(Z = 1\), average atomic mass \(A\approx1.00794\). So \(n = 1 - 1 = 0\) (for the most common isotope, protium).

Step8: For nitrogen (N)

Atomic number \(Z = 7\), average atomic mass \(A\approx14.0067\). So \(n = 14 - 7 = 7\).

Step9: For silver (Ag)

Atomic number \(Z = 47\), average atomic mass \(A\approx107.8682\). So \(n = 108 - 47 = 61\).

Step10: For gallium (Ga)

Atomic number \(Z = 31\), average atomic mass \(A\approx69.723\). So \(n = 70 - 31 = 39\).

Step11: For bismuth (Bi)

Atomic number \(Z = 83\), average atomic mass \(A\approx208.9804\). So \(n = 209 - 83 = 126\).

Step12: For rubidium (Rb)

Atomic number \(Z = 37\), average atomic mass \(A\approx85.4678\). So \(n = 85 - 37 = 48\).

Step13: For molybdenum (Mo)

Atomic number \(Z = 42\), average atomic mass \(A\approx95.94\). So \(n = 96 - 42 = 54\).

Step14: For argon (Ar)

Atomic number \(Z = 18\), average atomic mass \(A\approx39.948\). So \(n = 40 - 18 = 22\).

Step15: For cesium (Cs)

Atomic number \(Z = 55\), average atomic mass \(A\approx132.90545\). So \(n = 133 - 55 = 78\).

Step16: For silicon (Si)

Atomic number \(Z = 14\), average atomic mass \(A\approx28.0855\). So \(n = 28 - 14 = 14\).

Step17: For lead (Pb)

Atomic number \(Z = 82\), average atomic mass \(A\approx207.2\). So \(n = 207 - 82 = 125\).

Step18: For zirconium (Zr)

Atomic number \(Z = 40\), average atomic mass \(A\approx91.224\). So \(n = 91 - 40 = 51\).

Step19: For potassium (K)

Atomic number \(Z = 19\), average atomic mass \(A\approx39.0983\). So \(n = 39 - 19 = 20\).

Step20: For sulfur (S)

Atomic number \(Z = 16\), average atomic mass \(A\approx32.065\). So \(n = 32 - 16 = 16\).

Step21: For iodine (I)

Atomic number \(Z = 53\), average atomic mass \(A\approx126.90447\). So \(n = 127 - 53 = 74\).

Step22: For livermorium (Lv)

Atomic number \(Z = 116\), and assume an atomic mass of \(293\) (synthetic element, mass of most - stable isotope). So \(n = 293 - 116 = 177\).

Step23: For flerovium (Fl)

Atomic number \(Z = 114\), assume an atomic mass of \(289\) (synthetic element, mass of most - stable isotope). So \(n = 289 - 114 = 175\).

Step24: For copernicium (Cn)

Atomic number \(Z = 112\), assume an atomic mass of \(285\) (synthetic element, mass of most - stable isotope). So \(n = 285 - 112 = 173\).

Step25: For darmstadtium (Ds)

Atomic number \(Z = 110\), assume an atomic mass of \(281\) (synthetic element, mass of most - stable isotope). So \(n = 281 - 110 = 171\).

Answer:

Tungsten: 110
Nickel: 31
Fluorine: 10
Iron: 30
Sodium: 12
Hydrogen: 0
Nitrogen: 7
Silver: 61
Gallium: 39
Bismuth: 126
Rubidium: 48
Molybdenum: 54
Argon: 22
Cesium: 78
Silicon: 14
Lead: 125
Zirconium: 51
Potassium: 20
Sulfur: 16
Iodine: 74
Livermorium: 177
Flerovium: 175
Copernicium: 173
Darmstadtium: 171