MCQ 11 Mark
Which one of the following is a correct electronic configuration of sodium?
- A2,8
- B8,2,1
- C2,1,8
- D2,8,1.
Answer
View full question & answer→- 2, 8, 1.
50 questions · timed · auto-graded
Explanation:
Isoelectronic Species are those atoms which have the same electronic configuration or same number of electrons. For eg- N3-, O2-, F-, Ne, Na+, Mg2+, Al3+ are a series of isoelectronic species.
Explanation:
Isobars are the atoms of different elements with same mass number but different atomic numbers.
Explanation:
The first model of an atom was given by J.J. Thomson. According to him, an atom consists of a sphere of positive charge with negatively charged electrons embedded in it.
Explanation:
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content. Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies. Carbon-14 is also passed onto the animals that eat those plants.
Explanation:
As the mass numbers are different, the correct option is (c). They have the same number of protons.
Option:
Explanation:
The number of electrons are equal to the number of protons so the atomic number of the element X will be 15. For the representation purpose $_{15}^{31}\text{X}$ is correct for the element.
Explanation:
Explanation: Atomic number and the number of electrons in magnesium atom is 12.
So, electronic configuration is 2, 8, 2 (because 12 = 2 + 8 + 2).
An atom is a positively charged sphere with electrons embedded in it.
Explanation:
Thomson's model of atom states that:
An atom consists of a positively charged sphere with electrons embedded in it.
Total positive and negative charges in the atom are equal in magnitude. So, atom is electrically neutral.
Explanation:
The particles present in the nucleus of an atom are the proton and the neutron.
Electrons are revolving around the nucleus in circular orbits.
Explanation:
Atomic number of element X is 8.
Electronic configuration is 2, 6. It will gain 2 electrons to complete its octet; so, its valency is 2.
Atomic number of Y is 4.
Electronic configuration is 2, 2. It will lose 2 electrons in order to completely fill its outermost orbit. So, the valency of Y is also 2.
Explanation:
Rutherford suggested highly charged centrally concentrated small volume called as atomic mass and this region is known as nucleus of atom and gave the nuclear model of atom.
Explanation:
Since most of the alpha particles in Rutherford's experiment passed through the atom undeflected, he concluded that most of the space inside an atom is empty.
He also postulated that most of the mass of the atom is limited to a small volume inside the atom, called nucleus.
Explanation:
Bohr model of an atom states that only those orbits are allowed where angular momentum of electron are integral multiple of $\frac{\text{nh}}{2\pi}$ These orbits have quantized energy and angular momentum associated with electron.
The model can be applied to hydrogen or hydrogen-like atoms to explain their line emission spectrum.
Explanation:
The maximum number of electrons in first orbit or K-shell will be 2 × 12 = 2 and second orbit or L-shell will be 2 × 22 = 8.
Hence, if K and L shell is full, the total number of electrons in the atom will be 2 + 8 = 10.
Explanation:
Rutherford proposed that the electrons revolve around the nucleus in circular paths.
The electrostatic force of attraction between the nucleus and electron provides centripetal force (force towards the centre).
Explanation:
Rutherford used α-particles for scattering experiment. The $\alpha$−particles are Helium nuclei (He2+). Thus the answer for given question is Helium nuclei.
Explanation:
The total number of electrons present in oxygen is 8.
Therefore, for O electron configuration will be 1s22s22p4.
The distribution of electrons in oxygen atom is given by:
First orbit or K shell = 2(2n2 = 2 × 11 = 2)
Second orbit or L shell = 6(8 − 2 = 6)
Explanation:
Every element has a proton, neutron, and electron. The number of protons is equal to the atomic number, and the number of electrons is equal the protons, unless it is an ion. To determine the number of neutrons in an element you subtract the atomic number from the atomic mass of the element.
Explanation:
Given that, number of electrons in element X = 15 and number of neutrons = 16 Atomic number = number of protons = number of electrons in neutral atom = 15 Mass number = number of protons + number of neutrons = 15 + 16 = 31.
Explanation:
As the number of protons is same but the number of neutrons is different, the mass number of the two oxygen atoms is different. So, these two are isotopes of each other.
Explanation:
The observation that some alpha particles returned on their original path showed the presence of nucleus in the centre of an atom.
Explanation:
J.J. Thompson gave the first model of an atom.
Explanation:
Metals and non-metals both can have valency 1.
Metals which have 1 valence electron and non-metals which have 7 valence electrons, have valency 1. It is because, metals loose their 1e“ and non-metals gain 1e“ to complete their octet.
Explanation:
The valency shell means the outermost shell or orbit of an element which has valence electrons or outer electrons in it.
The atomic number of calcium is 20 and its electronic configuration is 2, 8, 8, 2 which shows that the outermost orbit or valency shell contains 2 electrons.
Explanation:
The chemical properties of an atom depend upon the atomic number.
From the atomic number, we can get valence electrons that determines the chemical properties of it.
Explanation:
Atomic no. 14 is silicon with configuration of 2, 8, 4 so it need four more electron to complete octet and have valency of 4.
Explanation:
A cathode ray is a beam of electrons in a vacuum tube traveling from the negatively charged electrode (cathode) at one end to the positively charged electrode (anode) at the other, across a voltage difference between the electrodes. They are also called electron beams.
Explanation:
Isotopes are atoms with the same number of protons but that have a different number of neutrons. Since the atomic number is equal to the number of protons and the atomic mass is the sum of protons and neutrons, we can also say that isotopes are elements with the same atomic number but different mass numbers.
Explanation:
Contains has three isotopes, Protium, Deuterium, and Tritium. All these contain only one electron and one proton. The only difference is in their neutron number.
Protium contains one electron, one proton, and zero neutrons.
Deuterium contains one electron, one proton, and one neutron.
Tritium contains only one proton and electron, and two neutrons.
So, Deuterium is the isotope which has an equal number of electrons, protons and neutrons.
Explanation:
Magnesium ion, Mg2+ has 10 electrons; so, its electronic configuration is 2, 8.
Explanation:
Tritium (3H) is the only radioactive isotope of hydrogen. The nucleus of a tritium atom consists of a proton and two neutrons.
Explanation:
Element X can’t form anions as the outermost orbit contains only 1 electron. The atom will rather lose this electron to complete its octet and will become a cation.
Explanation:
When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.
Explanation:
A hydrogen atom 11HH11 has 1 proton and 1 electron, but it does not have any neutron.
Explanation:
Atoms react to achieve an octet in the outermost shell. This can be done by sharing, gaining or losing electrons.
Explanation:
When alpha particles were bombarded on a gold foil, most of the alpha particles passed through undeflected.
This result indicates that most of the volume of a gold atom consists of unoccupied space.
This experiment is called the Rutherford experiment.