An atom has the following electron configuration . 1s^ 2 2s^ 2 2p^ 6 3s^ 2 3p^ 6 4s^ 2 How many valence electrons does this atom have ? 2
3
5
11

Check the correct box to describe the periodic trends in electronegativity. electronegativity across a period: decreases. increases. electronegativity down a group: decreases. increases.

Water (2510 g ) is heated until it just begins to boil. if the water absorbs 5.09×105 j of heat in the process, what was the initial temperature of the water?

Select the correct answer from each drop-down menu.describe what happens to a carbon-11 atom when it undergoes positron emission.the decay of a carbon-11 atom _1_, and this causes it to emit _2_.options for 1: > changes a neutron into a proton> changes a proton into a neutron> is hit with a neutron> reconfigures its protons and neutronsoptions for 2: > a negatively charged electron-sized particle> a positively charged election-sized particle> two atoms and several neutrons> two neutrons and two protons