All atoms can be identified by the number of protons and neutrons they contain. The number of protons present in the nucleus of an atom of potassium - 42 is 19.
The particles which are smaller in size than an atom are called subatomic particles. An atom contains three sub atomic particles, they are protons, electrons and neutrons. The positively charged particles are called protons whereas the negatively charged particles are electrons.
The neutrons are chargeless particle. Here K - 42 is a radioactive isotope which has the atomic number 19. So the number of protons is 19 and the number of neutrons is:
A = Z + N
N = A - Z
= 42 - 19 = 23
The number of protons or electrons is the atomic number whereas the mass number is the sum of protons and neutrons.
Thus the number of protons is 19 and neutrons is 23.
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the correct answer is 7897.0 Joules
All mixtures are made up of 2 or more elements or compounds.
All mixtures are made up of solutions
All mixtures are made up of compounds.
All mixtures are made up of elements.
All mixtures are made up of two or more elements or compounds.
Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.
Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:
1)Molecular compounds where in atoms are joined by covalent bonds.
2) ionic compounds where atoms are joined by ionic bond.
3)Inter-metallic compounds where atoms are held by metallic bonds
4) co-ordination complexes where atoms are held by co-ordinate bonds.
They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.
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Answer:
Answer the first ine made up of 2 or more.....
Answer:
Se + 2e- => Se-2
Explanation:
Ions are electrically charged particles, formed due to the gain or loss of electrons by an atom.
There are two types of ions cations and anions. An element that loses their electrons and forms positive ions are cations while metals and element that gains one or more electrons and forms negative ions are anions.
Selenium is an atom with atomic number 34 and represented as Se. The electronic configuration of Se is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4. Selenium will gain 2 more electrons to complete it p orbital and form an ion Se-2.
The equation is as below:
Se + 2e- => Se-2
b. The cations in the salt bridge will migrate to the anode half-cell
c. The cathode will gain mass
d. The anode will lose mass
e. Reduction will occur at the cathode