Answer:
- The standard form of a chemical element is the natural mixture of several isotopes of the same element, which is atoms with the same number of protons but different number of neutrons, while an isotope is a particular kind of atom with a definite number of neutrons.
Explanation:
A <em>chemical element</em> is a pure substance formed by atoms with the same atomic number (number of protons). This is because it is the number of protons what identifies an element.
For example: oxygen is a chemical element, so oxygen is formed by only atoms of oxygen, and the atomic number of those atoms is 8, because every oxygen atom has 8 protons.
Nevertheless, some atoms of oxygen, may have different number of neutrons. Isotopes are different kind of atoms of the same element, which only differ in the number of neutrons. So, some atoms of oxygen will have 8 neutrons, other 9 neutrons, and other 10 neutrons (those are the stable isotopes of oxygen).
That difference in neutrons, is generally accepted that, does not modifiy substantially the chemical properties of the element, but the mass number. So, the isotopes with more neutrons wil be heavier, and the isotopes with less neutrons will be lighter.
- Mass number = number of protons + number of neutrons.
In general a chemical element is formed by a mixutre of isotopes of the same element.
Answer:
by heart beat camel lives
JJ Thomson proved John Dalton's theory wrong, as Thomson discovered the electron. This showed that there were particles that were smaller than an atom, despite Dalton claiming that the atom is the smallest unit of matter.
Answer:
Metals in nature are found in rock form, mineral forms etc..
Half-life is basically how long it takes for a radioactive molecule to get to 1/2 of its original mass.
so if sodium 24 mass was 5g and it's half life was 24years then:
after every 24years 1/2 of 5g would have decayed. so in 48years there will only be 2.5g left.
