Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.
In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.
Answer:
Energy is added (postive enthalpy)
Explanation:
Ice melting means solid turns into liquid. Solid is more stable than liquid thus you must put in energy to weaken the forces of solid and turn it into liquid. Thus, you must put in energy to melt ice. This makes the enthalpy of the system to be positive.
Answer:
false; the purpose of antibiotics is to kill bacteria
Explanation:
Actually, there are only about 100 atoms that have been yet discovered. But each element has many different kinds of atom. For instance, carbon. Do you know carbon has more than 30 or 50 different types of atoms? Well, how? There are isotopes. Don't think that there is only one carbon atom which has 6 electrons and 6 protons and 6 neutrons. There are more. C-13 has 6 electrons and 6 protons and 7 neutrons. While, C-14 has 6 electrons and 6 protons and 8 neutrons. I just showed you three stable isotopes of carbon(element). But, what is really an isotope?? Did you notice that all of these atoms had the same number of protons and electron but different numbers of neutrons? This is really an isotope. Well, if an atom takes a few more electrons or gives off a few electrons, it still stays the same element/ atom type. Just like that an element can have atoms of different neutron number. It may be less or more. It doesn't affect the atom much: just makes an isotope. But it does affect the atomic mass number or radioactivity of an atom. So, an element can have many different forms of isotopes of its atoms. In this way, being only 100 atoms, there can 1000 atoms or (more than that!).
To make it more clear-
Definition of ISOTOPE: <span>any of two or more forms of a </span>chemical<span> element, having the same number of protons and electrons in the nucleus, or the same atomic number, but having different numbers of neutrons</span>
HOPE YOU UNDERSTOOD THE MATTER:-))
