The amount of a radioactive isotope present in a certain sample at time t is given by A(t) = 500e^-0.02828t grams, where t years is the since the initial amount was measured. How long will it take for the amount of the isotope to equal 317 grams

The freezing and boiling point of a substance changes as the air pressure around it changes. for example, at a lower air pressure (higher altitude) it is easier for water molecules to escape from liquid into the air. in a high altitude city such as denver, colorado compared to a sea-level city such as houston, texas, water

What does every magnet possess? a. iron metal b.strong magnetic field c.repulsion d.north and south poles

Up of elements with the same number of valence electrons. vertical column in the periodic table of elements such as alkali metals or halogens. a horizontal row of elements in the periodic table. this is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table. periodic trend these are the highly reactive elements located in group 1 of the periodic table. these elements have one electron in their outer energy level which makes them highly reactive with water and halogens. these are the reactive elements located in group 2 of the periodic table. these elements have two electrons in their outer energy level which makes them reactive with water and halogens. alkaline earth metals these are the group 3 or d-block elements. these dense metals with high boiling points can have different oxidation states and all are solid at room temperature with the exception of mercury. transition metals this is the highly reactive family of elements with 7 valence electrons. this is an element with full valence shell, very unreactive. this is a group of elements with few valence electrons that conducts heat and electricity. one of a class of elements having properties intermediate to metals and nonmetals. this is a type of element that has many valence electrons, not a conductor.