What is true about an element?
What is true about an element?
An element is a substance that is made entirely from one type of atom. For example, the element hydrogen is made from atoms containing a single proton and a single electron. All isotopes of a particular element have the same number of protons, but have a different number of neutrons.
Which of the following are true for element?
Which of the following are true for an element? (i) Atomic number = number of protons + number of electrons (ii) Mass number = number of protons + number of neutrons (iii) Atomic mass = number of protons = number of neutrons (iv) Atomic number = number of protons = number of electrons.
What is true about elements in each group?
The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons. They are the electrons involved in chemical bonds with other elements. Every element in the first column (group one) has one electron in its outer shell.
Which statement about a compound is true?
Compounds have a particular set of characteristics. Because the molecules of a compound are always exactly the same, the properties of the compound will always be exactly the same. For example, water will always freeze at zero degrees Celsius and boil at 100 degrees Celsius.
What are the two main categories of matter?
Classifying Matter Matter can be classified into several categories. Two broad categories are mixtures and pure substances. A pure substance has a constant composition.
What is the same about elements and compounds?
On first glance, elements and compounds might appear different, yet they share many similarities, like being made up of atoms and having bonds linking their atoms together. Elements and compounds also share the qualities of being both pure and homogeneous substances.
What is the similarities and differences of elements and compounds?
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds.
What do we get when two or more elements are combined Class 9?
Answer. When 2 or more elements are combined chemically i.e. through chemical reaction, then “compound” is formed.