# Atomic Mass

## Atomic mass is the mass of protons, neutrons, and electrons in a single specific atom.

### What instrument measures mass? Traditionally a balance was used to measure mass. Objects of known or accepted mass was balanced against another object of unknown mass. When the balance was level the two pans had the same mass. The term balance or scales is still used even though there is no balance used. The scales were the pans that the objects sat on. Now electronic balances are used that gauge the mass of the objects. While you can measure mass with a spring loaded scale, it is less accurate than a balance as it relies on a spring loaded to a specific acceleration of gravity for any given mass. A change in altitude will change the results given on the scale, due to the actual change in gravitational force (it is small at only about 0.031% error for every kilometer increase in altitude)*. A balance would experience no such change as the mass of an unknown quantity is compared to the mass of a known quantity, thus negating any effects of gravity. Another instrument that measures mass is an inertial balance. An inertial balance doesn't require gravity to work, so it can be used in space. It measures the mass of an object by attaching it to a spring and seeing how it affects the spring's period of oscillation. Very tiny masses can be measured directly (using a "massometer"). But we normally use scales, which measure weight, which is directly proportional to mass (a property of matter equal to its resistance to a change in speed or direction of travel). The mass of an object is the same everywhere in the universe. Its weight, however, changes depending upon its location: a bowling ball has greater weight on the surface of the Earth than it does on the Moon. Great confusion arises when people interchange units of weight with units of mass. Scientists, particularly physicists, are very careful about not using the terms interchangeably, but regular folks have no choice for practical applications. For example, when you weigh a regulation ten-pin bowling ball, the scale will tell you it "weighs" between 4 and 7 (3.63 to 7.27 actually) kilograms, even though the kilogram is, technically speaking, a unit of mass, not weight. You can also measure the mass of an object using a scale, as long as you factor in the gravitational constant (G). For instance, in an environment with only 1/2 the gravity of That on earth, you would have to double the weight displayed on the scale to determine the actual mass. As an example, 10Kg of lead in a 0.5G environment would only "weigh" 5Kg on a scale...half as much as on earth, even though its mass is unchanged.

### What is the mass number of an atom? A mass number is the total number of protons and neutrons found in an atom. To find the mass number, you must know the number of neutrons in that particular isotope of the element and then add the atomic number (same as the number of protons) to it. When this number is definite it is called a nuclide and the symbol is written with a superscript giving the mass number and a subscript giving the atomic number (number of protons) placed in front of atomic symbol: 2311Na. It can also be written after the elements name, sodium-23. Do not confuse this with the atomic number, which is the number of protons. .

### If an atom has 6 protons 8 neutrons and 6 electrons what is the atomic mass of the atom? The atomic mass is the number of protons, plus the number of neutrons. In this case, 8 + 6 = 14. Furthermore, the six protons (atomic number) tells me that this is carbon; the six electrons tell me that this is a carbon atom, rather than a carbon ion (an ion is when the number of electrons does not equal the number of protons, making the atom electrically non-neutral). The eight neutrons tell me that this is an isotope (in other words, a version) of carbon called carbon-14, which happens to be mildly radioactive; and therefore useful to archaeologists in dating human artifacts.

### How do calculate atomic mass? Number of protons plus the number of neutrons (electrons don't matter as they have such a small mass).

### Why is atomic number better than atomic mass for organizing the elements in the periodic table? Atomic number is a unique number for each element. No two elements have the same atomic number. Atomic number is also the number of protons in the nuclei of the atoms of any given atom. Atomic mass, however, is the number of protons, neutrons and electrons. The number of neutrons can vary with different isotopes of the same element, this means that atomic mass can vary with different isotopes. So atomic number does not vary, but atomic mass does, so it is more logical to use atomic number to organize the elements. In addition, when the elements are arranged according to atomic number into seven rows and 18 columns, it becomes evident that there are certain trends that occur across the periods, and that elements in the same group have similar properties.

### Mass number vs atomic mass? atomic mass is the number of protons in an atom mass number is the number of protons plus neutrons in an atom

### Is the atomic mass of hydrogen 3? The atomic mass of the most common form of hydrogen is 1. There are isotopes of hydrogen with a mass of 2 (deuterium) and 3 (tritium), but they are rare.

### How do you calculate effective atomic mass? Aeff=(Zeff)/((Z/A)eff) Zeff=wi*Zi wi is weight fraction in ith element in compound. for example water has 0.112 H and 0.888 O. (Z/A)eff=wi*Zi/Ai

### What is mass? Mass is the quantitative measure of inertia, or the resistance of a body to a change in motion. The greater the mass, the smaller is the change produced by an applied force. Unlike weight, the mass of an object remains constant regardless of its location. Thus, as a satellite moves away from the gravitational pull of the Earth, its weight decreases but its mass remains the same. In ordinary, classical chemical reactions, mass can be neither created nor destroyed. The sum of the masses of the reactants is always equal to the sum of the masses of the products. There is another meaning that I think you could mean also. Mass is the religious sermon catholics attend, usually on a Sunday, but also on a saturday.

### Atomic mass used in a sentence? The atomic mass of an element is the weighted average of the masses of all the stable isotopes of the element (if it has any), weighted by the natural occurrence levels of the isotopes in the elements as found on earth or in the atmosphere.

### What has a lower atomic mass cobalt or nickel? Interestingly, nickel has a lower atomic mass (58.693) than cobalt (58.933), even though cobalt has a lower atomic number (27) than nickel (28).

### What does the atomic mass equals the number of? An isotope's mass number is the sum of the protons and neutrons in each atomic nucleus of the isotope.

### What does atomic mass and atomic number represent? The atomic number is the number of protons in the nucleus of an atom. (Note: that in a neutral atom the number of protons in the nucleus is also equal to the number of electrons the atom has) The atomic mass is the mass (weight) of all the components of the atom but is dominated by the nucleus composed of protons and neutrons. Basically atomic mass is how many times an atom of an element is heavier than an atom of hydrogen, (whose atomic mass is taken as unity ). (Note: atoms with the same atomic number [ie an element] may have slightly differing atomic masses. This is because atoms can have differing numbers of neutrons in their nucleus. These variations in atomic mass are called "isotopes" of that element) I have made a related link below showing you a Periodic Table of the Elements. The numbers on the table are the atomic number of the element. An element's atomic number represents the number of protons that are present in the nucleus of an atom in that element. The atomic number represents the number of protons there is in that element. It also represents the number of electrons for that particular element only if the atom is atomically neutral and is not electrically charged. Typically, an atom does not lose protons so it is reliable to base this number on the number of protons in an atom as opposed to the number of electrons, seeing that electrons can be easily lost.  