Answer is: the atom is the smallest known particle of matter.
John Dalton claimed that atom is indestructible and a<span>ll atoms of a given element are identical in mass and properties.
</span>Thomson discovered electron and found the first evidence for isotopes<span> of a stable element.</span>
Answer:
74
Explanation:
we know,
atomic number = number of protons
so,
atomic number = 74
Oxygen 47 Hydrogen 63
Silicon 28 Oxygen 25.5
Aluminum 7.9 Carbon 9.5
Iron 4.5 Nitrogen 1.4
Calcium 3.5 Calcium 0.31
Sodium 2.5 Phosphorus 0.22
Potassium 2.5 Chlorine 0.03
Magnesium 2.2 Potassium 0.06
Titanium 0.46 Sulfur 0.05
Hydrogen 0.22 Sodium 0.03
Carbon 0.19 Magnesium 0.01
All others <0.1 All others <0.01 Living matter
<span>C. It is in the row below and therefore more reactive </span>
