Mass, relative atomic

The atomic mass without units is perhaps more correctly called the relative atomic mass (relative to the mass of carbon-12 as 12 u). We will take the common approach of calling both 12.011 u and 12.011 the atomic mass of carbon. 

Atomic masses of the elements are called relative masses. What does this mean and to what isotope are the atomic masses relative ... 

For many years an atomic weight of 44 1 was accepted for scandium, but in 1923 Aston showed that the element had no isotopes and that its atomic mass relative to oxygen 16 was 45. As a result of fresh chemical investigation, the atomic weight 45 1 was accepted by the International Committee in 1925, and this value is accepted to-day (1950). 

Atomic mass relative to C =12. Atomic weight of elements is given on the same scale. 

TTie following values have been obtained by the most precise mensurements with the mass-spectrograph for atomic masses relative to = 16, i.e. on the physical scale (Aston, Mass spectra and isotopes , Arnold, 1942, p. 116)... 

Elements Atomic mass Relative electronegativity (Poling scale) Ionization energy, kj-mole" Charge Ionic radius at coordination number 6,r k. Ionic potential... 

Atomic mass relative to =12. Atomic weight is given on the same scale. Half-life in decimal notation, ps = microseconds ms = milliseconds s = seconds m = minutes h = hours d = days and y = years. 

Element Symbol Atomic Number Atomic Mass (Relative to Carbon-12)... 

Except in cases where the numbers express relative quantities, such as atomic masses relative to the mass of carbon-12 or specific gravity, it is essential to include units with numbers. In addition to correctly identifying the type and magnitude of the quantity expressed, the units are carried through mathematical operations. The wrong unit in the answer shows that something has been done wrong in the calculation and it must be checked. 

Name Symbol Atomic no. Atomic mass (relative)... 

Relative atomic mass, relative formula mass and molar mass... 

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