C. Not each element has a known neutron number
Answer:
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Explanation:
The two elements that have the same properties as sodium are potassium and rubidium .
<h3>What is periodic table?</h3>
The periodic table is an arrangement of the elements in order of increasing atomic number.
From the list, the two elements that have the same properties as sodium are potassium and rubidium .
Proton has an atomic number of 20 and a mass number of 40. The number of electrons is the same as the number of protons. Given that the atomic number is the number of protons present, we have 20 electrons and 20 protons.
Number of neutrons = Mass number - Number of protons
= 40 - 20 = 20 neutrons
Learn more about periodic table:brainly.com/question/11155928
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<u>Answer:</u> It repels positive ion and attracts negative ion.
<u>Explanation:</u>
There are 2 types of ions:
1. Cations: These ions are positively charged ions which are formed when a substance looses electrons.
2. Anions: These ions are negatively charged ions which are formed when a substance gains electrons.
It is known that, like charges repel each other and unlike charges attract each other.
As, it is given that the substance is positively charged, so it will attract anion and repel cation.
