Which answer best describes an atomic nucleus?
The nucleus is the positively charged centre of an atom and contains most of its mass. It is composed of protons, which have a positive charge, and neutrons, which have no charge.
Which describes a nucleus?
Nucleus. A nucleus is a membrane-bound organelle that contains the cell’s chromosomes. Pores in the nuclear membrane allow for the passage of molecules in and out of the nucleus.
What is an atomic nucleus quizlet?
Nucleus. The positively charged center of the atom made up of nucleons called protons and neutrons.
What makes atomic nucleus?
Atomic nuclei consist of electrically positive protons and electrically neutral neutrons. These are held together by the strongest known fundamental force, called the strong force. The nucleus makes up much less than . 01% of the volume of the atom, but typically contains more than 99.9% of the mass of the atom.
Which describes the function of the nucleus?
The nucleus controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information.
What is nucleus describe its parts and functions?
The nucleus is a spherical-shaped organelle that is present in every eukaryotic cell. The Nucleus is the control centre of eukaryotic cells. It is also responsible for the coordination of genes and gene expression. The structure of the nucleus includes nuclear membrane, chromosomes, nucleoplasm, and nucleolus.
How was the atomic nucleus discovered?
In 1911, Rutherford, Marsden and Geiger discovered the dense atomic nucleus by bombarding a thin gold sheet with the alpha particles emitted by radium. … From this observation, they concluded that almost all the atomic matter was concentrated in a tiny volume situated at the atome center, the atomic nucleus.
Why is the atomic nucleus important?
The atomic nucleus holds 99.99% of the mass of the atom. The number of protons is the atomic number and identifies which element it is a part of. The atomic mass is the number of protons and neutrons that can all be found inside the nucleus.
What contains the nucleus?
The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell’s genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
What experiment discovered the nucleus?
Rutherford’s gold foil experiment
Rutherford’s gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
Which statement about the atom’s nucleus is correct the nucleus is made of?
Which statement about the atomic nucleus is correct? The nucleus is made of protons and neutrons and has a positive charge. Atoms have an equal number of protons, which each have a charge of +1, and electrons, which each have a charge of -1.
Does the nucleus of an atom rotate?
If the distribution of mass and/or charge inside the nucleus becomes non-spherical then the nucleus will be able to rotate. The rotation is termed “collective” because many of the nucleons (the protons and neutrons) are involved.
What did Rutherford’s experiment prove about the atomic nucleus?
The gold-foil experiment showed that the atom consists of a small, massive, positively charged nucleus with the negatively charged electrons being at a great distance from the centre.
Who discovered nucleus and by which experiment?
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
Which statement about the alpha particle scattering experiment provides evidence for the existence of the nucleus?
The experiment involved firing alpha particles at thin gold foil, where the number of alpha particles scattered at various angles were counted using a detector. This provided evidence for the existence, charge and small size of the nucleus.
What is the experimental evidence for the presence of small nucleus containing most of the mass and all of the positive charge in the atom?
The Geiger–Marsden experiments (also called the Rutherford gold foil experiment) were a landmark series of experiments by which scientists learned that every atom has a nucleus where all of its positive charge and most of its mass is concentrated.
Why did Rutherford conclude that atoms contain a nucleus?
Rutherford concluded that atoms contained nuclei based on the refraction of alpha particles when passed through a thin sheet of gold foil.
Which of the following provides evidence for the existence of atomic energy levels?
The uniformity of the emission and absorption spectra are evidence for atomic energy levels.
What did Rutherford’s scattering experiment provide evidence for?
Rutherford’s experiment showed the existence of a nuclear atom – a small, positively-charged nucleus surrounded by empty space and then a layer of electrons to form the outside of the atom. Most of the alpha particles did pass straight through the foil. The atom being mostly empty space.
What observation did Rutherford lead to conclude that the nucleus of atom is very small but heavy mass?
The electrons were said to be around the atom and very small in size compared to the nucleus. This experiment, called the alpha-scattering experiment, established the fact that an atom is mostly empty and all the charge and mass is in the nucleus.