Table of Contents
How does the number of elements change?
An elements atomic number will never change, that is because the atomic number is its “identity.” The atomic number is the number of protons that is contained in the nucleus, if you add a proton you change the element. Therefore, an elements atomic number will never change.
What is Mendeleev’s law?
the law that the properties of the elements are periodic functions of their atomic numbers. Also called Mendeleev’s law. (originally) the statement that the chemical and physical properties of the elements recur periodically when the elements are arranged in the order of their atomic weights.
What is the law of periodicity?
The Periodic Law states that the physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number.
Why did the original periodic table have gaps in it?
Mendeleev left gaps in his table to place elements not known at the time. By looking at the chemical properties and physical properties of the elements next to a gap, he could also predict the properties of these undiscovered elements. The element germanium was discovered later.
Which of these can vary without changing the identity of the element?
ANSWER: (b) mass number can vary without changing the identity of the element.
Can the mass number vary without changing the identity of an atom?
the number of protons and neutrons in an atom. the number of protons in an atom. The mass number is O the number of protons and neutrons in an atom. Neither the mass number nor the atomic number can vary without changing the identity of an atom.
Why do elements in the same group show similar properties?
So, we can say that elements in a group have the same physical and chemical properties because their atoms have the same number of valence electrons or same valence shell electronic configuration.
What is Newlands law?
law of octaves, in chemistry, the generalization made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements.
Why do elements in the same group behave similarly?
The elements in a group often look and behave similarly, because they have the same number of electrons in their outermost shell — the face they show to the world. Group 18 elements, on the far right side of the table, for example, have completely full outer shells and rarely participate in chemical reactions.
How is the modern periodic table different from Mendeleev’s original periodic table?
The main difference between Mendeleev and Modern Periodic Table is that Mendeleev’s periodic table orders the elements based on their atomic mass whereas Modern periodic table orders the elements based on their atomic number.
Can the mass number vary without changing the element?
the number of protons in an atom. The mass number is O the number of protons and neutrons in an atom. The mass number can vary without changing the identity of an atom. The mass number and the atomic number can both vary without changing the identity of an atom.